Male and female F-344 rats were exposed at 0, 25, or 247 ppm triethylamine (TEA) vapor, 6 hr per day, 5 days per week for up to 28 weeks in order to characterize the subchronic organ system toxicity. Rats were weighed biweekly and scheduled sacrifices were performed following about 30, 60, and 120 days of exposure. No statistically significant treatment-related effects on organ weights, hematology, clinical chemistry, or electrocardiographic indices were observed. Body weight gain was not affected by TEA treatment. No physiologic or pathologic evidence of cardiotoxicity was seen in rats exposed to either TEA concentration for up to 28 weeks. No gross or histopathologic lesions attributable to TEA exposure were noted in any of the organs examined, including the nasal passages. This latter finding is in marked contrast to previously reported findings from this laboratory in which squamous metaplasia, suppurative rhinitis, and lymphoid hyperplasia were found in the respiratory epithelium of F-344 rats exposed to the structurally related chemical, diethylamine, under the same conditions as this study (Lynch et al., 1986).