One hundred and twenty-one subjects with decompression disease (DD) treated by the Spanish Navy between 1969 and 1986 are reported. The mean age of the victims was 31.4 +/- 7.2 years. The leading cause of DD was the partial or complete omission of decompression. The development of type I DD (57%) (basically joint pain) was more common than type II (43%) (neurological vestibular and/or pulmonary features). In 84.3% of cases the clinical features began within 6 hours of the end of immersion, although only 61.5% were treated during the initial 6 hours. When therapy was delayed for longer than 6 hours, the rate of sequelae was considerably increased. The rate of complete recovery after treatment in a compression chamber was 92.7% for type I DD and 71.1% for type II DD.