An epidemiologic study of Crohn's disease was carried out in the Province of Palermo, Italy, between 1987 and 1989. The incidence of first hospitalization was prospectively evaluated in this period. A total of 103 patients (59 males, 44 females) were diagnosed. The standardized annual incidence was 2.7/100,000. The incidence was quite constant during the 3 years of the study (1987: 2.9/100,000; 1988: 2.4/100,000; 1989: 2.99/100,000). Incidence rates were slightly higher in men than in women. The disease had a bimodal age distribution in female (with peaks at age 20-29 and 60-69) and males (with peaks at age 30-39, 40-49). No cases were observed at age 0-9. The incidence of Crohn's disease in southern Italy is comparable to that reported in northern Europe.