The exterior of Tom's Restaurant on the corner of West 112th Street and Broadway, near Columbia University, is often shown on the show as the exterior of Monk's, though the interiors were shot on a sound stage. The restaurant consists of a number of booths, tables, and a counter. Jerry, Elaine, George and Kramer normally sit in the first or second booth from the entrance. Throughout the show's run, the chance to sit in the first booth — and thus be included in a Seinfeld scene — was auctioned off for charity.
The owner of the fictional café is Larry the Cook, played by Lawrence Mandley. He first appears in "The Outing" during season 4. In the season 4 finale, "The Pilot", Elaine is incensed that Monk's "new management" is hiring nothing but big-breasted waitresses. The new owner is identified as Mr. Visaki (played by Al Ruscio) and the well-endowed employees turn out to be his daughters. However, in the season 5 episode, "The Wife", Larry has returned as the owner/manager and appears in that role throughout the remainder of the show's run.
Monk's cashier's name is Ruthie Cohen, played by Ruth Cohen. Cohen appears in 101 of the 180 Seinfeld episodes, more episodes than any character outside of the four main cast members.
Jerry refers to a competing coffee shop, Reggie's, as "the bizarro coffee shop." According to George, it has practically the same menu but is disliked by Jerry and Elaine (in "The Soup") for its failure to serve an "egg white omelette" or the famed "big salad." In "The Pool Guy" George eats at Reggie's because there is no room for him at the table in Monk's, with Susan taking up the fourth spot.
Jerry Seinfeld and writer Larry David in creating "Seinfeld" called the coffee shop Monk’s because there was a poster of the jazz great pianist Thelonious Monk in the office in which they were writing, and they just needed a name. 
- Larry the Cook, the owner/manager/cook.
- Ruthie Cohen, the cashier at Monk's, is seen behind the register in most scenes set in in the café, and appeared in 101 episodes. In "The Gum" she is seen on a horse, and aggravates George by saying, "Your car's on fire."
- Kelly, a waitress who openly flirts with George in "The Soup". She is turned off by his mentioning an affinity for the word "manure." She is only waitressing to get money to travel to Europe and quits at the episode's end because her handmade hairclips have started selling.
- Paco, a line cook at Monk's. He's alluded to in "The Strike" when George attributes a rubber band in his soup to Paco's cooking.
- The Blonde Waitress, who George is certain is giving him "the finger" by pointing to the menu and scratching her face while talking with him. The actress is Lauren Bowles.
- Olive, a cashier whom Kramer dated in "The Pie".
- Babu Bhatt, who worked as a busboy after Jerry helped get him hired in "The Visa".
- A Portuguese waitress with whom George had a brief relationship in "The Abstinence".
- "New York City Travel Guide: Tom's Restaurant, New York City". Virtual Tourist. Retrieved 2014-05-10.