The show centers on a smart-mouthed dog who is incredibly obese, so much to the point that he is ball-shaped with small, stubby legs. Other characters include Little Costumed Buddy, Piranha Mae, and Onion Boy. The group fights crime in the fictional neighborhood of "Neighbourhood X" and they try to fight for justice but often fail humorously.

• Fat Dog Mendoza (Voiced by Mark Acheson) – The main protagonist. He is a massively obese dog who is smart, and solves problems with Buddy.
• Little Costumed Buddy (voiced by Kathleen Barr) – Fat Dog's best friend. A boy who loves pretending to be a hero and wants to be a real one someday. In one instance when Fat Dog teaches him how to bowl, he accidentally calls him "Little Costumed Danny")
• Piranha Mae (voiced by Erin Fitzgerald) – Buddy's best friend.
• Cruddy McFearson (voiced by Brian Drummond) – Buddy's bully.
• Onion Boy (voiced by Ian James Corlett) – A friend and classmate of Buddy.
• Doctor Rectangle (voiced by Peter Kelamis) – Buddy's Dad.
• Polly-Esther (voiced by Teryl Rothery and Pauline Newstone, respectively) – Buddy's teachers and neighbours who are siamese twins. Despite having a single body, her two heads are separate in personality and opinions.

Development for the series began in March 1994, when Sunbow explored producing a show based on the one-shot comic. For many years, it remained on Sunbow's development slate as the studio classified it as a "Raw" property due to it only existing as a one-shot comic.

In December 1997, production for the series started with the completion of the preliminary bible for the series to convert the adult nature of the comic into a kids property, and to retain the qualities of the characters. Sunbow began to ship the show off to other companies as a co-production deal, who were mainly impressed with the Little Costume Buddy character.

In March 1998, Sunbow began to find a European partner for the series, which they found Cartoon Network Europe as broadcaster and TMO-Loonland as co-producer. The former noticing the show could appeal to the European audience, and the latter being that their unique animation style would work for a series like Fat Dog Mendoza. By September, both companies signed in September 1998, with TMO-Loonland's signing allowing the series to fulfill European content requirements. The funding for the series was split for 50% by Sunbow, 35% by TMO-Loonland, and 10%–15% by Cartoon Network Europe. It also allowed Cartoon Network Europe to fulfill their two-production deal with Sunbow, with fellow show The Cramp Twins filling the other half.

By 1999, the production was confirmed for an Early-2000 delivery from Cartoon Network Europe, who would hold first-run rights to the series.^[4]

Season 1 edit

Season 2 edit

The series originally premiered on Cartoon Network UK in February 2000, and remained on the channel until 2005 (mainly being repeated late-at-night). Channel 5 later acquired free-TV rights and began airing the show in 2001 as part of their The Core teen block, and later transitioned to Milkshake FM.^[5][6]

The show also aired on several other Cartoon Network feeds, including Cartoon Network MENA.^[7]

Over the next few years, the show was pre-sold by TV-Loonland to other broadcasters and companies, like Nox Music in Russia,^[8] Retelsat in Spain,^[9] and ZigZag in Poland.^[10]

In Australia, the series aired on Nickelodeon.^[11]

The show also re-ran on KidsCo in a small number of countries.^[12]

The series never aired in the United States.^{[citation needed]}

In 2000, home video distributor Maverick announced they had acquired the British home video rights to Sony Wonder's catalogue in the United Kingdom.^[13] The company released single VHS volume of the series in October 2000, containing the first three episodes in production order: "Other Side of the Moon", "Forgotten Fat Dog", and "Power Play".^[14]

• Fat Dog Mendoza at retrojunk.com
• Fat Dog Mendoza at IMDb