Propylene oxide was evaluated for neurotoxicity in 30 male Fischer 344 rats (F0 generation from a two-generation reproduction study) receiving whole body exposure to nominal concentrations of 0, 30, 100, or 300 ppm 6 hours/day, 5 days/week, for approximately 24 weeks. Observational battery tests were performed at approximately 8, 16, and 24 weeks of exposure. Also preformed prior to sacrifice were hindlimb grip strength test and an open-field activity test. After sacrifice an extensive histopathologic examination of the central and peripheral nervous system was conducted. There were no differences in the pre-sacrifice test results between the treated and control groups. Mild neuroaxonal dystrophy (eosinophilic spheroids) in the region of the nucleus gracilis was present in the majority of control and treated animals; the incidence and severity of the condition was more prevalent in the controls than tin he high dose animals.