A medical report from the Third Whitbread Round the World Race (1981-1982) is presented by the doctor on board the Swedish entry, who was also the contact doctor for the fleet. The race is the longest ocean race in the world at 27,000 nautical miles. It is divided into four legs with the yachts being offshore for 4-6 weeks on each leg. The medical preparation for the Swedish entry and the organization for the contact between the 28 participating boats are presented. The problems of medical interest during the race, as well as the possible dangers on board and their prevention, are listed and discussed. It is concluded that good medical preparation for the race is of great importance for the results.