Comic Relief has apologised for the offence taken by viewers after Jonathan Ross used the "f-word" during a live broadcast on this year's Red Nose Night in March.
The Broadcasting Standards Commission has upheld more than 30 viewer complaints about the slip, making it the ninth censure handed out to the presenter.
Even though the offending word was aired after the 10.30pm watershed, the commission said it was unacceptable for Ross to use bad language because many children were still watching.
The latest censure comes just weeks after Ross was rapped for making disparaging comments about disabled children on his Radio 2 morning show.
Listeners complained after he made fun of a colleague for looking like "a slightly challenged youth, like you would get on a Variety Bus."
Previously, Ross received complaints following his remarks about the facial disfigurement of stroke victims, the rape drug Rohypnol and hospice patients.