To determine if there is a widespread problem with personal watercraft (jet ski) injuries throughout the United States, we reviewed the hospital records of patients who were treated at this institution for injuries incurred while they were operating a motorized personal watercraft or jet ski. All of the patients were under the age of 19 and suffered severe fractures or lacerations. To assess the extent of the problem with these injuries regionally, we collected data from 8 midwestern states for 1989. Sixty-four personal watercraft accidents involving 90 victims were reported in the survey. Fifty-three of 90 patients sustained fractures, lacerations, or head injuries. Seventy-nine of 90 were under age 25, and 24 patients were under 16 years of age. The need for supervision and the potential for serious injury while operating personal watercraft is supported by these findings.