"Re: using the 'N' word in an interview, I am sorry," he Tweeted. "I should have never said the word and I will never say it again."
Mayer used the slur when discussing whether he's accepted by rappers like Jay-Z and Kanye West as one of their own.
"Someone asked me the other day, 'What does it feel like now to have a hood pass?,' " Mayer told Playboy. "If you really had a hood pass, you could call it a n---- pass But I said, 'I can't really have a hood pass. I've never walked into a restaurant, asked for a table and been told, 'We’re full.' "
The remark didn't wash with his 3 million Twitter followers. After one fan Tweeted that Mayer should enter rehab, the singer responded, "they don't make rehab centers for being an a-hole."
Mayer said nothing about his other controversial comments about his sex life with former flame Jessica Simpson – likening her to "sexual napalm" – but Simpson did appear to allude to them on her own Twitter page.
"Interesting day so far," she wrote. "Hmm. At least I am boxing 2-a-days this week."