Tommy Pickles (voiced by E.G. Daily, and Tami Holbrook in the unseen pilot): He is the baby who always helps his friends and is quite an adventurer. He is also the undesignated leader of the babies. Tommy is named after the first son of Paul Germain, one of the show's creators.

Dil Pickles (voiced by Tara Strong): Tommy's younger brother, a true baby (i.e. not a toddler like the other children). Introduced in the first Rugrats movie.

Angelica Pickles (voiced by Cheryl Chase): Tommy and Dil's cousin who always bosses the "babies" around, being the oldest at 3 years old. She enjoys lying to the toddlers and distorting their perception of reality. However, she always acts perfect around the adults.

Chuckie Finster (voiced by Christine Cavanaugh up to 2002 due to motherly leave, Nancy Cartwright to series' end): Tommy's best friend. He will always do anything to help his friends, despite being scared.

Phil and Lil DeVille (Both voiced by Kath Soucie): Twins (boy and girl) that have everything in common. Both enjoy playing in the mud and like to eat worms and/or insects.

Kimi Finster (voiced by Dionne Quan): Chuckie's step sister, introduced in the second Rugrats movie, Rugrats in Paris. Kimi is a very happy girl who is always smiling, and likes to be an adventurer like Tommy.

Susie Carmichael (voiced by Cree Summer): A neighborhood friend who is about seven months younger than Angelica. When around, Susie often stands up to Angelica when she taunts the young toddlers. She also has two older brothers, Edwin and Buster and an older teenage sister, Alisa.

The other babies and the other kids
Harold Frumkin is a kid in Angelica and Susie's pre-school class. Voiced by Pat Musick.

Alisa Carmichael is the Carmichaels' oldest teenage child. Voiced by Kath Soucie.

Buster Carmichael is the Carmichaels' cheeky child. Voiced by Kath Soucie.

Edwin Carmichael is the Carmichaels' brain-trust. Voiced by Cree Summer.

Timmy McNulty is the oldest of the five McNulty boys. Voiced by Tara Strong.

Todd and Ty McNulty are the twins in the McNulty clan. Voiced by Tara Strong and E.G. Daily.

Terry McNulty is the another one of the McNulty boys. Voiced by Grey DeLisle.

Teddy McNulty is the youngest of the McNulty boys. Voiced by Grey DeLisle.

The adults

Stu Pickles (voiced by Jack Riley of The Bob Newhart Show fame): Tommy and Dil's father and brother of Drew. Absent-minded toy inventor. Married to Didi Pickles. Birthday is October 23 according to the All Growed Up special.

Didi Kropotkin Pickles (voiced by Melanie Chartoff): Tommy and Dil's mother. A part-time schoolteacher and married to Stu. It is revealed that she is coulrophobic, just like Chuckie Finster. Didi is also a Jewish-Russian-American since having 2 Russian-Jewish parents and may also have been born in Russia.

Louis-Kalhern-Pickles (aka: Lou Pickles) (voiced by David Doyle from 1991, until his death in 1997, and Joe Alaskey; 1997-Series End) Tommy, Dil and Angelica's grandfather and Stu and Drew's father. Lived with Stu's family for the first few seasons and often babysat the children.

Trixie McGee Pickles: is Tommy, Dil, and Angelica's deceased grandmother; Drew and Stu's mother; and Lou's first wife. She has never appeared in person on the show because she died long before the show began, and is only seen in Grandpa Lou's flashbacks. Little is known about her, although at one point, it is mentioned that she worked on one of Estes Kefauver's presidential campaigns in the 1950s.

Lulu Pickles (voiced by Debbie Reynolds): Lou's second wife; he met her in the hospital where she works as a nurse. Also Tommy, Dil, and Angelica's step grandmother and Stu and Drew's stepmother.

Drew Pickles (voiced by Michael Bell): is married to Charlotte, is Angelica's father and Stu's older brother. A well-paid accountant, Drew does not always get along with his brother, and the two often bicker over petty problems. His catchphrase (when addressing Angelica) is "Princess". Drew Pickles is also famous on the Internet. He is one of the main characters in the Barney Bunch series of YouTube videos, which are made using Microsoft Sam. Some other characters include Barney, Ronald McDonald, and various Disney actors.

Charlotte Pickles (voiced by Tress MacNeille): Angelica's workaholic mother. CEO of her own company and married to Drew. She tries to be a good mother, but is usually sidetracked by business interests. Is often shown talking on her Mobile phone to "Jonathan" (her co-worker), who was shown several times during early episodes of the series.

Betty DeVille (voiced by Kath Soucie): Phil and Lil's mother. Quite the jock and women's-libber. Married to Howard. Helps operate the Java Lava Coffee House with Chas Finster.

Howard DeVille (voiced by Philip Proctor, formerly of The Firesign Theatre): Phil and Lil's mild mannered father. Often overpowered by and cringing towards his wife, Betty.

Chas Finster (voiced by Michael Bell): Widower; Chuckie's father, from whom he inherited his adenoidal whine. Married Kira in the second Rugrats movie. Kimi's stepfather. Runs the Java Lava Coffee House with Betty.

Kira Finster (voiced by Julia Kato): Kimi's mother and Chuckie's stepmother. Married Chas in the second Rugrats movie. Operates the Java Lava Coffee House with her husband. She somewhat plays the straight man to the rest of the adults' wackiness, but she enjoys showcasing and trying new things, as opposed to a lot of the rest of them. Kira is also Japanese.

Melinda Finster (voiced by Kim Cattrall): is Chuckie's birth-mother. She loved flowers, and she died a few months after Chuckie's birth, long before the show began. She is only seen in flashbacks, although she is referenced several times in the series.

Lucy Carmichael (voiced by: Cheryl Carter (1992, 1997-Series End), Lisa Dinkins (1993), Hattie Winston (The Rugrats Movie): Susie's mother and Randy's wife. She is a Harvard-educated "wonder mom" and does a lot of cool things. She is also a doctor. She delivered Dil.

Randy Carmichael (voiced by: Ron Glass): Married to Lucy Carmichael & is Susie's father. Randy is a writer for the famous cartoon Dummi Bears Show.

Great Aunt "T" and Uncle Charles (Voiced by Irma P. Hall and Bill Cobbs): are the great aunt and uncle of Susie and her siblings.

Boris and Minka Kropotkin (voiced by Michael Bell and Melanie Chartoff), Didi and her brother Ben's Jewish parents. Eastern European immigrants who are always complaining that it wasn't this way in the "Old Country". Boris periodically babysat the babies (when Grandpa Lou was out for the night).

Ben Kerpackter (voiced by Jeff Bennett), Didi's younger brother and Elaine's only husband. In his first appearance, he is about to be married to a woman named Elaine, (referring to the characters of the same names in The Graduate) who briefly disappears before the wedding because of cold feet. The married couple appear again to babysit the Rugrats as experience for having their own children, but unpleasantly discover that raising children may not be so simple if they act like Angelica.

Aunt Miriam (voiced by Andrea Martin): Known as the "money game queen" because she plays poker, and constantly irritates her younger cousin, Grandpa Lou Pickles. It is implied her relationship with Lou as a child mirrors Tommy and Angelica's relationship.

Shirley and Marvin Finster (voiced by Miriam Margolyes and Stacy Keach): Chas's parents, and Chuckie and Kimi's grandparents.

Colleen McNulty (Voiced by Theresa Ganzel): is the McNulty boys' mother.

Conan McNulty (Voiced by Michael Keenan): is the McNulty boys' grandfather and Lou's rival. They've both had a rivaled childhood, compteting against each other all the time.

Larry and Steve (Both voiced by Scott Menville): are two teenage boys, who always seem to have different odd-jobs, such as painters; movie theater attendants; grocery store employees; etc. They are named after two producers of some episodes.

Jonathan (Voiced by Rene Auberjonois in 1995 and Dan Castellaneta from 1998 until the series end): is Charlotte's meek assistant, whom she constantly yells at. He was originally portrayed with purple skin, but had fair skin in later appearances.

Dr. Lipschitz (voiced by Tony Jay): A child psychologist who Didi and Chas commonly refer to for help in raising the babies.

Taffy (Voiced by Amanda Bynes): is Lulu's grandniece, who was hired as a regular babysitter for the babies. She is the lead singer of a band.

Miss Weemer is Angelica and Susie's teacher in pre-school.

The pets

Spike (voiced by Bruce Willis only in Rugrats Go Wild!): The Pickles' brown hound dog. Tommy deeply admires him. (Spike was once voiced in a very old Rugrats episode in which Chuckie had a dream that he and the other babies went into Spike's doghouse. In the doghouse, Spike was drinking tea and spoke with a British accent here his voice was provided by Michael Bell who sometimes performed his vocal effects).

Fifi (not voiced): Purple poodle, who was originally a Parisian stray which Spike fell in love with in the second Rugrats movie and became his girlfriend.

Spiffy and Pepper (not voiced): Purple and brown (respectively) puppies adopted by the Stu Pickles and Chas Finster households. The offspring of a union between Spike and Fifi. (Note: In US showings of "Mutts In A Name", Puppy's identified as "Pepper", as a result of a viewer poll).

Fluffy (not voiced): Angelica's cat who Angelica loves dearly, but who always causes trouble for the others, particularly Spike.

Melville (not voiced): Chuckie's first pet, who was a Pillbug that died in the first episode he aired in. At the time of death, Chuckie was in the midst of training Melville to perform circus tricks.

Fictional TV characters

Reptar (not voiced): A big green dinosaur reminiscent of Godzilla. Tommy and the other Rugrats love him; Reptar products such as cars, clothes and candy are frequently seen on the show. Reptar was a main character in Rugrats in Paris and had his own theme park called Euro Reptarland. There was a giant Reptar robot there too, which the babies piloted and fought against Jean Claude. He has also had his own ice show, which Lou believes is "sheer brilliance". The babies interrupted it looking for a lizard which they believed was "Baby Reptar".

Robosnail (not voiced): Reptar's arch enemy. Robosnail is a mechanical snail with snapping pincers. He made a special guest appearance in Rugrats in Paris, controlled by Jean Claude. Robosnail and Reptar fought throughout Paris and he wound up falling into a river.

Dactar: a big Pterodactyl who fights Reptar on TV. He resembles Rodan from Godzilla.

Thorg: (voiced by Phil Procter)a giant gorilla who is an enemy of Reptar. In the episode "Toy Palace," Tommy and Chuckie activate a large robotic Thorg, who chases them through the store, repeating his catchphrase, "Thorg hungry! Thorg want eat!" He is made to resemble King Kong. He'd been sent back in time.

Captain Blasto (Adam West): From the early seasons of the show. A spaceman who hosts his namesake show, a low budget locally made kids program that is reminiscent to the Captain Video series of the 1950s. In Super Hero Chuckie, Chuckie, Angelica, Stu and Drew go to see the show made at the television studio, where they learn the secret about how Captain Blasto flies (a cable that attaches to his costume).

The Dummi Bears: A cartoon watched by the babies. It is a spoof of the Care Bears (though the name is more a play on the Gummi Bears). Susie's father Randy Carmichael was a writer for the show, and in one episode, the babies are taken to a movie theater to see the Dummi Bears movie (they escape from their parents to go see the reptar movie, and cause havoc in the movie theater).

Blocky and Oxwinkle (Blocky voiced by June Foray): Stu and Drew's favorite cartoon as babies. They are an obvious parody of Rocky and Bullwinkle.
Yuri and Svetana (Svetana voiced by June Foray): A pair of villains who try to trick and get rid of Blocky and Oxwinkle, and calling them "Elk and Weasle". They are a parody of Boris and Natasha, and their nicknames for Blocky and Oxwinkle is a parody of "Moose and Squirrel".

Alan Quebec: Voiced by Alex Trebek, he hosted "Super Stumpers," the fictitious game show on which Didi Pickles appears in the episode "Game Show Didi."

The Mega Hyper Heroes: The super heroes that the babies watch on TV. The babies imitated the characters by calling themselves the "Mega Diaper Babies". They only appeared in the episode "Mega Diaper Babies". They appear to be based on the Fantastic Four.They were voiced by Neil Ross, Michael Bell, and Kath Soucie.
The Mole People: Reptar's arch enemys.

Cynthia: Angelica Pickles favorite doll. Based on the American doll, Barbie. Cynthia's name possibly comes from the British doll "Sindy".

Real People

Chick Hern: Appeared in the episode "Touchdown Tommy", as the sports anchor of a football game, voiced by himself.

Pat Sajak: Appeared in the episode "Chuckie is Rich", as the host of a Publishers Clearing House-like contest, where the grand prize was $10 million and was won by the Finsters. The character is voiced by himself.