The relationship between the health status and physical characteristics of 185 U.S. Navy divers and their risk for experiencing decompression sickness was examined utilizing historical cohort design. Data on multiphasic medical examinations performed on these men between 1972-1978 were obtained. Cases of decompression sickness before and after examination were identified. Divers who did experience decompression sickness either before or after examination had significantly higher measures of skinfold thickness and weight when compared to those who remained free of decompression sickness. Those divers in the highest quartile of each of three significant skinfold thicknesses measured had risks for decompression sickness that were generally 9 to 10 times as great as those calculated for the combined lower 3 quartiles and 5 to 6 times as great as the average crude risk calculated for all Navy divers over the past 5 yr. These findings suggest that obesity may be a contributory factor to the occurrence of decompression sickness.