We studied 47 hospitalized motorcyclists admitted through the Massachusetts General Hospital emergency room during a 1-year period. Four factors were studied: 1) hospitalization charges, 2) hospitalization lengths, 3) medical insurance profiles, and 4) patterns of injuries. The mean hospitalization charges were +15,114. The total hospital charges for this group of patients were nearly +700,000. These figures excluded the costs of subsequent admissions, surgeons' fees, rehabilitation, vocational training, legal suits, and loss of wages. Sixteen per cent of the charges were uncollectable. Forty-six per cent of the patients were uninsured. The average hospitalization was 22 days. The mean age was 22 years and 90% of patients were less than 30 years old. Eighty-five per cent of the patients sustained at least one fracture. Lower extremity fractures occurred in 60%, open fractures in 55%, and tibia fractures occurred in 33% of the patients. Associated head, chest, or abdominal injuries occurred in 40% of the patients. Patients with multiple fractures, open fractures, and grade 3 open tibia fractures had substantially higher hospital bills.