Fatality records for American cave-diving fatalities (n=368) occurring between 1969 and 2007 were examined and circumstances preceding each death categorized. Safety rules breached were noted in each case. The number of deaths per year peaked in the mid-1970s and has diminished since. Drowning was the most frequent cause of death, most often after running out of gas, which usually followed getting lost or starting the dive with insufficient gas. Compared with untrained divers, trained divers tended to be older, died at deeper depths and further inside caves, carried more cylinders of gas and more often died alone. Untrained divers were more likely to have dived without a guideline, without appropriate number of lights and/or without adequate gas for the planned dive. Since running out of gas was associated with the greatest number of fatalities for trained divers, we recommend that gas management rules should receive the greatest emphasis in cave diving courses.