Cain received 37.1 percent of the nearly 2,700 votes cast. Perry, who had been favored to win, came in second with 15.4 percent.
Former Massachusetts Gov. Mitt Romney came in third with 14 percent.
Former Pennsylvania Sen. Rick Santorum followed with a little less than 11 percent.
Perry's second-place finish in the straw poll came just days after he faltered in a debate in Orlando, Fla. The governor was a late entrant into the Republican primary and quickly led national polls, but he has stumbled in recent weeks.
His defense of in-state tuition rates for illegal immigrants put him on the wrong side of the GOP's conservative base. His rivals worked to exploit his opposition to a fence along the U.S.-Mexican border and his support of a mandatory vaccine for girls against a sexually transmitted disease.
The Associated Press contributed to this report.