In Italy, most foreign residents are between the ages of 19 and 40 years and are sexually active. Data from the Italian national STD surveillance system, a nationwide network of public STD clinics, show that over 10% of the reported cases of STD are diagnosed among these individuals. Furthermore, the mobility of foreign populations and problems with access to health care facilities can contribute to the spread of these diseases. This report presents data on over 4000 STD patients and on 1103 AIDS patients among foreign residents in Italy and includes a discussion of strategies for providing adequate STD care and for promoting prevention.