Impairment on neuropsychological tests during steady-state drug use and withdrawal, and after discontinuation of benzodiazepines, was studied in primary benzodiazepine-dependent patients. One group of patients was tested before and the other group after the initiation of a gradual tapering-off of the drug, and both groups were tested approximately 1 year later. At the initial assessment, both groups of patients showed impairment on most of the tests of general intelligence and on several of the tests in the Halstead-Reitan battery, as well as on a test of nonverbal memory, in comparison with healthy controls. At follow-up the patient groups had reached the level of the control group. This study confirmed earlier observations of neuropsychological deficits in long-term benzodiazepine-using patients and demonstrated that these changes are at least partly reversible by discontinuing drug intake.