We investigated the efficacy and safety of augmenting risperidone with fluvoxamine for the treatment of residual positive and negative symptoms in patients with chronic schizophrenia who had shown an incomplete response to risperidone. A total of 30 patients completed the open trial over a 12-week period during which fluvoxamine was added to risperidone. The result from the positive and negative syndrome scale (PANSS) and Simpson-Angus extrapyramidal effects (S-A) scale were examined at baseline, 1, 2, 4, 8 and 12 weeks of treatment. There were no significant differences in PANSS positive, negative and general psychopathology scores, or in S-A scale scores at any point during the treatment. These results suggest that fluvoxamine appears to be ineffective in augmenting the risperidone treatment response in chronic schizophrenic patients. Further controlled trials will be needed to confirm this observation.