Bis(2-ethylhexyl) phthalate (CAS No. 117-81-7) was evaluated for subchronic toxicity. The test substance was administered in the diet ad libitum at 0, 1,000, 5,000, 10,000, and 25,000 ppm to rats (10/sex/group) for 4 weeks. In the highest dose group, there were 7/20 deaths, and clinical signs in this group included hunched posture, thin appearance, hypoactivity, tremors, urine stains, dyspnea, and rough coat. Body weights were decreased in the two highest groups. Animals from the 25,000 ppm group had significantly lower mean erythrocyte counts, hemoglobin, and hematocrit values as compared to controls. At 5,000 ppm and higher, there were kidney lesions, gross hepatic lesions, hepatocellular hypertrophy, and hepatic necrosis. Absolute and relative testes weights were markedly lower in the 25,000 ppm group and absolute and relative liver weights were markedly higher in the 10,000 and 25,000 ppm groups as compared to controls. Testicular atrophy was noted in all 25,000 ppm males. Thymic atrophy of both sexes and the absence of corpora lutea in females were also noted in the 25,000 ppm group. The NOEL of this study was 1,000 ppm.