A study of all serious childhood immersion accidents (both drowned and near-drowned cases) is reported from Hawaii. This is a total population-based survey of 140 consecutive cases (0--15 years) occurring during the five-year period (1973--1977. Age-specific, sex-specific, and osmolality-specific (salt versus fresh water) data are presented both for survivors and fatalities. The overall annual drowning rate of 3.1 per 100,000 children at risk is low, for a water-oriented society. The survival rate following loss of consciousness in the water is 73 per cent. There is no evidence from this study that osmolality affected the probability of survival. The rank order of importance of drowning sites is swimming pools, surf, sheltered salt water bathing, domestic bath tubs, fresh water streams, salt water canals, and garden fish ponds. Specific accident rates, by sex, outcome, and site of immersion are also presented. No secular trend in the rate of drowning was observed in this study. Comparison with the only other available total population survey (Australia) of childhood immersions reveals common epidemiological and demographic patterns in modern urban societies and suggests that safety regulations play a role in reducing swimming accidents and fatalities in children.