This study examined diagnostic practices and neuroleptic use at four general medical and surgical VA medical centers. Most effects were as expected, e.g., patients administered neuroleptics during a prior hospitalization and who exhibited more psychotic symptoms were more likely to be diagnosed with schizophrenia than with a mood disorder. However, the centers differed in their diagnostic practices after adjusting for such differences in symptomatology. As a result, patients were more likely to receive neuroleptic medication when treated at certain hospitals relative to others even though these differences followed directly from differences in diagnostic practices. Further research is needed to determine the extent to which these different diagnosis practices reflect variation in training, theoretical orientation, documentation, or justification for particular psychiatric practices. Regardless, they have significant legal and professional ramifications.