Brand name and generic prescriptions for 12 drugs were surveyed at 33 pharmacies in the Rochester, New York, area to determine how frequently generic prescriptions were filled with a product other than the major brand, and at a savings to the consumer. Generic prescriptions for ampicillin, erythromycin, propoxyphene, and dioctyl sodium sulfosuccinate were often filled at prices lower than comparable brand name prescriptions. Occasional, but often substantial, savings were obtained for papaverine, pentaerythritol tetranitrate, and conjugated estrogens. No savings were obtained for penicillin V, chlorpheniramine, diphenylhydantoin, sulfisoxazole, or methenamine mandelate. The pharmacists included in the survey identified correctly a mean of 18.5 out of 22 drugs as to whether products other than the major brand were available. A sample of physicians identified correctly a mean of 14.1 drugs. Pharmacists who were better informed as to which drugs were available generically were more likely to stock alternative products and more likely to charge lower prices on generic prescriptions than on brand name prescriptions.