Cases of lightning-related deaths and injuries that occurred in Florida in 1978-87 were reviewed to determine the factors involved, to quantify the morbidity and mortality related to lightning strikes, and to describe epidemiologically the injuries and circumstances involved. Statewide information on deaths was obtained from death certificates, autopsy reports, and investigative reports. Information about morbidity was obtained from the Florida Hospital Cost Containment Board data base and the National Climatic Data Center data base for all Florida counties, as well as from hospitals in selected counties. Lightning-related deaths totaled 101 in Florida during the period 1978-87, an annual average of 10.1. Eight percent of the victims were from other States. The overall yearly death rate for State residents was 0.09 per 100,000 population, with the highest rate being that for men aged 15-19 years, 0.38 per 100,000. Thirteen percent of victims were females. The ratio of lightning-related injuries to deaths in Florida was estimated at about four to one. Thirty percent of all deaths were occupationally related. The first strikes of lightning from a thunderstorm may be the most dangerous, not in terms of impact, but because of the element of surprise. During thunderstorms, people may seek shelter under isolated trees because they believe erroneously that a tree offers protection from lightning, or perhaps because their top priority is to escape from rain rather than lightning. People may not seek adequate shelter during thunderstorms because they do not know the dangers of remaining outdoors or their judgment is impaired by drugs or alcohol.