The aim of the study was to evaluate the epidemiology and the diagnostic, clinical and therapeutic aspects of immigrants affected by tuberculosis, hospitalized in 35 Italian Infectious Diseases Clinics during 2003. The data obtained showed that 300/2392 (12.5%) patients had active tuberculosis, 10.3% of whom had concomitant HIV infection. 53% of the patients were legal residents and were assisted by the National Health Service; 48.3% came from African regions. The mean length of residency in Italy at the time of hospitalization was 4 years. The main clinical forms were pulmonary (66%), lymph nodal (15.3%) and bone TB (5.3%). Drug resistance was demonstrated in 16% of cases with 9% cases of resistance to isoniazid, 8.2% to streptomycin, 5.1% to pyrazinamide, 2.6% to ethambutol, 2.6% to rifampicin; in 5.3% of cases a multiple resistance was demonstrated. A complete adherence to treatment was achieved in 213 patients. Statistical analysis disclosed a significant correlation between compliance with treatment and legal citizenship status. In conclusion, TB still represents an important disease among immigrants. Improved living conditions, both in countries of origin and in Italy, especially in the first few years, would certainly decrease the incidence of TB.