181 fatal cases of diseases and work-related accidents recorded in the years 1985-1994 among seamen and fishermen were analyzed. The highest mortality rate and fatal accident rate were noted in seamen. They were higher than those pertaining to workers employed on land. The respective rates for Polish fishermen were lower than those reported in other countries. The main causes of death at sea were sea catastrophes, injuries, drowning, poisoning and circulatory system diseases. The most frequent were deaths during the day and not on the watch, being alone in the cabin. Limited access to qualified medical assistance during the voyage and frequent occurrence of sudden deaths reduce substantially the efficacy of help. Therefore, prevention of diseases and accidents is of crucial importance.