The therapeutic efficacy and safety of subcutaneously applied recombinant interferon alpha (IFN-α) at doses of 6X10⁶ IU/day (3 times/week) were investigated in 26 patients with classic Kaposi’s sarcoma. After a 6-month IFN-α administration 18 patients (69.23%) revealed a complete remission, 4 patients (15.38%) showed a partial remission and 4 patients (15.38%) were non responders. 12 out of 18 patients (66.66%) with complete remission relapsed within 23-46 months after discontinuation of therapy. Recurrences revealed an impressive therapeutic response to IFN-α requiring short periods of retreatment (6-10 weeks) with the same dosage. 6 patients (33.33%) are presently completing a 68-84 month follow-up without any evidence of recurrence. All patients but one revealed a transient flu-like syndrome including fever, fatigue, chills, headache and myalgias that were treated with paracetamol. Apart from a transient leukopenia observed in all patients but one and a transient neutropenia seen in 3 patients, no significant changes of laboratory parameters were observed. These findings indicate that the subcutaneous application of IFN-α represents an effective, easy to perform and well tolerated therapeutic approach to the classic form of Kaposi’s sarcoma, that leads to long remissions of the disease in a considerable number of patients, whereas recurrences are highly responsive to short periods of retreatment.