The purpose of this study was to assess the effect of switching to risperidone in the treatment of first-episode schizophrenia who had failed to respond to an initial-prescribed antipsychotic, olanzapine. Fifty-one patients with first-episode schizophrenia after unsuccessful treatment of olanzapine (the mean (S.D.) dosage: 16.4 (4.4) mg/day) were included in this switching study. Of the 51 patients, 43 (84.3%) completed the full 12-week trial and 8 (15.7%) dropped out. The mean dosage of risperidone at the endpoint (last observation) was 3.1 (2.0) mg/day. The total scores of Brief Psychiatric Rating Scales (BPRS) were significantly reduced from baseline to endpoint, especially in the positive and excitement factors (p<0.001). Responder rate (at least 20% decrease in BPRS total score plus final Clinical Global Impression score of 3 or less) was 35.3%. These findings indicate that the switching to risperidone could be one of the useful treatment options in this population.