A trial of three treatment schedules, consisting of 1% gamma benzene hexachloride (GBH) lotion applied head to toe and left on the body for 2, 6, or 12 to 24 hours was conducted on an island of 2,076 persons, approximately 70% of whom had clinical evidence of scabies. The island is situated off the north coast of the Republic of Panama. Examination at 1 month after therapy showed that both the 6-hour and 12- to 24-hour cure rate was high (96% and 98%). There was a significantly lower cure rate in the 2-hour group, in which only 82% were cured. Eleven to twelve percent of the subjects became infested in all groups, presumably due to contact with untreated persons with scabies on the island. A single 6-hour application of 1% GBH lotion appears to be adequate therapy for scabies if properly applied. The entire population at risk should be treated at the same time if possible to reduce or eliminate the risk of infestation. No adverse reactions to 1% GBH lotion were observed.