A Coast Guard spokesman says the crew of the M.S. Oosterdam determined early Sunday that the man needed to be hospitalized for treatment of pancreatitis.
The ship, of the Holland America Line, came within 36 miles of San Diego and a helicopter was sent to pick the man up.
He was flown to Scripps Memorial Hospital in La Jolla.
The ship was on a seven-day loop from San Diego to Mazatlan, Puerto Vallarta and Cabo San Lucas.