Elmer receives a large package, accompanied by a letter from his Uncle Judd. In the letter, Elmer is asked to take care of the enclosed rare Slobovian rabbit named Millicent until he arrives, and is promised five hundred dollars for his efforts. When he opens the box he discovers that Millicent is a huge, unattractive, female rabbit with an Eastern European accent. When Elmer shows Millicent her room, she trashes the room and cries uncontrollably on a couch.
Elmer talks to a doctor that says that Slobovian rabbits get lonely and need another rabbit to talk to. He goes out to lure a rabbit with a carrot, and catches Bugs.
When Elmer introduces Bugs to Millicent, her demeanor quickly switches from melancholic to amorous; she asks for a "laaarge keess", as she calls it. Most of the rest of the plot deals with Bugs' humorous attempts to evade Millicent's romantic advances; Bugs is often thwarted by a gun-wielding Elmer. After they dance to "Slobbovian Rock 'n Roll", with Bugs in a kilt for the performance, Bugs declares that they should elope. Bugs takes a rolled up sheet and holds it out the window for Milly to slide down, but lets go of the sheet as she is doing so, "Butterfingers."
As Millicent pounds on the door, Bugs goes and tells Elmer that Uncle Judd is at the door. Bugs offers a "bathrobe" for Elmer to slip into; as he steps into the hall, the "bathrobe" is revealed to be a bunny costume. When Elmer opens the door, Millicent becomes interested in Elmer instead, and chases after him off into the countryside. Bugs, at the door, says, "Ain't I the little matchmaker?"
- On CBS, Nickelodeon, ABC, and both the syndicated and Fox versions of Merrie Melodies Starring Bugs Bunny & Friends, the part where Bugs uses a goldfish to shield himself from Millicent's kisses was cut to remove the part where the goldfish is put back in the fishbowl, the goldfish takes out a pistol, returns inside his toy castle, and shoots himself, implied by the bubbles surfacing and making a gunshot sound when popped. (Interestingly, this scene was intact on CBS when the cartoon was shown as part of Bugs Bunny's Valentine.)
- On The WB!, the part where Bugs uses an electric fan to protect himself from Millicent's kisses, but her mouth destroys the fan, and then Millicent says, "Mmm, not bad for a beginner!" was cut. Interestingly, the goldfish suicide part wasn't edited on The WB!
- This short is notable as one of the few parings of Bugs and Elmer in which Bugs is not hunted throughout the entire picture (despite Elmer using his hunting rifle every time Bugs tries to escape throughout the entire cartoon), and also notable as a cartoon in which Bugs has a romantic encounter.
- This is the first time John W. Burton is a co-producer of a Warner Bros short, he would eventually become a full fledged producer the following year after Eddie Selzer's retirement.
- "Rabbit Romeo" is one of the few Robert McKimson-directed shorts to have Michael Maltese as its writer.
- This is one of the MERRIE MELODIES releases to use the 1957-59 blue Color Rings and the 1957-58 WARNER BROS. PICTURES INC., but closing was the 1955-56 season's rings instead of the 1957-59. The next cartoon, "Don't Axe Me", would have the first to have the 1957-59 rings on both titles.