Molly Norris, of Seattle, drew a cartoon in April to protest the decision by the US television channel Comedy Central to cancel an episode of the popular show South Park.
In her cartoon, Norris satirically proposed May 20 as an "Everybody Draw Mohammed Day".
An "Everybody Draw Mohammed Day" page quickly turned up on Facebook but Norris, writing on her website at mollynorris.com, said she had nothing to do with it.
"I did not 'declare' May 20 to be "Everybody Draw Mohammed Day," she said, adding that her idea was satire but "was taken seriously, hijacked and made viral".
"I never started a Facebook page; I never set up any place for people to send drawings to and I never received any drawings," she said.
"The vitriol this 'day' has brought out, of people who only want to draw obscene images, is offensive to Muslims who did nothing to endanger our right to expression in the first place," she said.
"I apologise to people of Muslim faith and ask that this 'day' be called off," she said.
The "Draw Mohammed" page has led to Facebook being blocked in Pakistan and sparked angry protests and condemnation from the foreign ministry, which denounced the "publication of blasphemous caricatures of our holy prophet."
The Facebook page on Tuesday had drawn over 89,000 fans - and a slew of crude photo-shopped pictures and caricatures.
The purported creator of the Facebook page said meanwhile that he started it to stand up for "freedom of expression."
Islam strictly prohibits the depiction of any prophet as blasphemous and Muslims across the globe staged angry protests over the publication of satirical cartoons of Mohammed in European newspapers four years ago.