The ability of a battery of genetic monitoring tests to detect occupational formaldehyde exposure in a population of a hospital autopsy service workers was investigated. Eleven exposed individuals and 11 matched controls were evaluated for sperm count, abnormal sperm morphology and 2 F-body frequency. Subjects were matched for sex, age and customary use of alcohol, tobacco and marijuana. Additional information was collected on health, medications and other exposures to toxins. Ten subjects were employed for 4.3 months (range 1 to 11 months) prior to the first sample and one was employed for several years. Formaldehyde exposures were episodic but with a time weighed average between 0.61 and 1.32 pm (weekly exposure range 3 to 40 ppm. hrs). Exposed and control subjects were sampled 3 times at 2 to 3 month intervals. Sperm morphology was also evaluated in B6C3F1 mice after 5 daily oral doses of 100 mg/kg formalin. No increase in abnormal morphology was detected in the treated animals.