Eleven patients with cutaneous T-cell lymphoma stages Ib-IV a were treated with a combination of interferon alfa-2a and photochemotherapy. The diagnosis was confirmed by histological and immunohistological investigations. During the initial treatment, interferon alfa-2a was given at a maximum dose of 9 million IU 3 times a week. Few patients received for a short time 9 million IU daily s.c. The total dose amounted to an average of 125 million IU. Simultaneously, photochemotherapy with a maximum single dose of 2 J/cm2 was applied. The total dose ranged between 7 and 62.9 J/cm2, which corresponds to an average dose of 22.6 J/cm2. After achieving a complete or partial remission the dose of interferon was reduced to 1.5 or 3 million IU, which was then maintained for long-term treatment 2 or 3 times a week. Photochemotherapy was given twice weekly for a minimum of 2 months and then stopped, depending on the course of the disease. The success of therapy was judged from the clinical and histological picture. The combination treatment was well tolerated and led to complete remission in 5 patients (45%) and a partial remission in 6 patients (55%) after the initial therapy which lasted for an average of 48 days. During the follow-up period, which now amounts to 2-13 months with under 1.5 or 3 million IU interferon, three patients have shown disease progression. One patient responded well to newly applied photochemotherapy and in two patients local tumors regressed after radiation.