Purpose: To report on the results of interferon-alpha 2a (IFN alpha) treatment in patients with Behcet uveitis unresponsive to conventional immunosuppressive therapy. Methods: We retrospectively analyzed the medical records of 44 patients who had been treated with IFN alpha between September 2001 and May 2005. The initial dose of IFN alpha was 6 MU/day in 37 patients (84.1%) and 3 MU/day in 7 patients (15.9%), and was gradually tapered after ocular inflammation was suppressed. Immunosuppressive agents were discontinued. Oral corticosteroids were discontinued or maintained at a dosage of less than 10 mg prednisone equivalent per day. Main outcome measures were recurrence of posterior or panuveitis attacks and changes in visual acuity. Results: Sixteen patients (36.4%) remained relapse free during treatment, whereas 28 (63.6%) patients had recurrent uveitis attacks. Four of these were considered treatment failures and were switched to other treatments. In the remaining 40 patients, the mean duration of treatment was 12.4 +/- 10.8 months (range 3-45 months). In 9 of 40 patients (22.5%) treatment could be discontinued 22.2 +/- 13.4 months after therapy, and 8 (20%) of these patients had sustained remission for up to 24 months. Three patients (7.5%) were switched to other therapies because of side effects. The frequency of uveitis attacks per 6 months was reduced from 1.6 +/- 1.2 to 0.8 +/- 0.9 in 26 patients who had a minimum follow-up of 6 months before and after IFN alpha therapy (p < 0.05). There was a significant improvement in visual acuity and this was preserved throughout follow-up in 38 (95%) of 40 patients. Conclusions: A partial or complete response was obtained with IFN alpha therapy in 91% of Turkish patients with Behcet uveitis refractory to conventional immunosuppressive treatment. Our results suggest that there may be differences in therapeutic efficacy and side-effect profile of IFN alpha in different patient populations. Comparative studies are needed to investigate this hypothesis.