Simpson and the exhibitor that invited him were asked to leave the National Sports Collectors Convention on Saturday because neither had sought permission to attend the event, said convention spokesman Bob Ibach.
Celebrities must receive prior approval to sign autographs at the show, he said.
Exhibitor Justin Communications had invited Simpson to sign memorabilia, officials said. When officials discovered Simpson was in attendance, security escorted him from the Donald E. Stephens Convention Center without incident.
Simpson was acquitted of murder after the 1994 stabbing deaths of his wife, Nicole Brown Simpson, and her friend Ronald Goldman. A civil jury in 1997 held Simpson liable for the killings and ordered him to pay the victims' survivors $33.5 million. Much of that judgment remains unpaid.
Just looking for the real killer of Nicole and Ron, who was cleverly hiding at the sports show.