The acute inhalation toxicity of diamylamine (CAS No. 2050-92-2) was evaluated in 6 groups of Sprague-Dawley rats (5/sex/group) exposed for 4 hours to diamylamine vapor in a environmental chamber at average metered concentrations of 43, 52, 60, 67, 75, and 82 ppm. All mortality occurred within 24 hours of exposure and an LC50 with 95% confidence limits calculated by the method of Litchfield and Wilcoxon was 66 (59-73) ppm. Among the decedents, tremors and clonic convulsions during exposure often heralded death; There were no other outward signs of pathology. During 14-week post- exposure observation, all but 4 females of the survivors gained weight. Examination of upper and lower respiratory tract, liver, heart, GI tract and kidneys from both study survivors and lethalities identified no gross pathology.