In the period 1971-1981, 1,835 cases of leprosy were reported in the United States; only 10% of these cases were indigenous. Since 1977, the number of new cases reported each year has risen because of an increase in imported cases of disease, a situation reflecting the increased number of refugees and immigrants who have entered the United States from areas endemic for leprosy. Forty-five of the 50 states reported cases. In only 25% of the imported cases were the patients known to have had leprosy at the time of immigration; the remaining 75% were diagnosed in this country. The highest rate of disease onset for this latter group occurred within 12 months after entry into the United States, but cases continued to be reported 10 years after entry. Active refugee resettlement programs have widely distributed persons with leprosy, contacts of diseased persons, and persons from endemic areas throughout the 50 states, a situation necessitating the development of expertise by medical professionals and public health officials in the diagnosis, treatment, and long-term follow-up of patients with leprosy.