The authors performed a clinical study of 255 patients with εlopecia areata retrospecitively in order to evaluate the clinical manifestation and the effect of treatment with intralesional injection of triamcinolone acetonide suspension from August, 1986 to February, 1991. The results were as follows : 1. The age distribution showed a peak incidence in the third decade(15.5％, 116/255) and average age was 29.6 years. 2. The most common site of involvement was the occipital region(54.1％) in males and the temporal region(51.0％) in females. 3. The effect of treatment in the group treated with intralesional injection of triamcinolone acetonide revealed no significant difference from the group treated with intralesional injection of tramcinolone acetonide and topical application of minoxidil solutior. 4. The area of the bald patch revealed statistically significant correlation with effect of treatment. But the other factors such as sex, age, history of pervious episode, duration and number of lesions were not contributory. These findings suggested that alopecia areata predominantly developed in male and showed excellent therapeutic effect in cases of bald areas less than 5㎠