Eric Geisman, 45, of Pawtucket, R.I., was strolling near the pool at the J.W. Marriott Grande Lakes resort in Orlando Monday when he accidentally stepped on the poisonous snake, the Orlando (Fla.) Sentinel reported.
He was taken by ambulance to the Dr. P. Phillips Hospital where he was placed in the intensive care unit.
"He's in a lot of pain," said Geisman's sister-in-law, Lyn Arruda. "We're not sure what to expect."
Arruda said Geisman was bitten on the left ankle and his left leg is still swollen.
Geisman and his wife were at the Marriott to attend a conference.
The general manager of the resort could not immediately be reached for comment, the Sentinel said.