Frankie Boyle has faced a wave of criticism as his controversial style was condemned by a prominent MP and mental health and disability campaigners.
Complaints have now been lodged with broadcasting watchdog Ofcom over three different parts of the comedian's Channel 4 series Tramadol Nights.
The use of the words "nigger" and "Paki" in Tuesday's episode were condemned by Conservative MP John Whittingdale who branded Boyle "a serial offender".
The MP, who is chairman of the House of Commons Culture, Media and Sport Select Committee, said: "The words are deeply offensive to a large number of people. I don't think even in comedy it is justified."
Channel 4 said the use of the words was "satirical", not racist. A spokesman said: "Channel 4 strongly refutes any suggestion we are endorsing or condoning racist language by our broadcast of Frankie Boyle's Tramadol Nights.
"This cutting edge comedy is clearly intended to ridicule and satirise the use of these words - Frankie Boyle was not endorsing them.
"Channel 4 would not have broadcast these words had they been used in a racist way. All the jokes highlight the unacceptable nature of this language."
Ofcom is already investigating Boyle's show after he made a controversial joke about model Katie Price's disabled son and a mental health charity said it had complained to Ofcom about a different sketch in a further episode.
Katie complained to Ofcom earlier this month after what she described as a "vile" joke about her son Harvey.
Mark Davies, director of communications at mental health charity Rethink, has written to the watchdog saying a sketch which parodied an advert designed to reduce the stigma around mental illness was misleading and offensive.