Tertiary-butyl acetate (TBAC) was tested for subchronic toxicity in rats and mice and reproductive toxicity in rats at inhalation concentrations of 0, 100, 400 or 1600 ppm. An oral maternal toxicity study was conducted in rats at dose levels of 0, 400, 800, 1000 and 1600 mg kg⁻¹ d⁻¹. In the inhalation studies, hematology, clinical chemistry, urinalysis, gross pathology and the majority of body weight and feed consumption values were unaffected. Exposure to TBAC at concentrations of 400 ppm and higher caused transient hyperactivity in mice and some evidence of increased motor activity counts in male rats at the 1600 ppm exposure level. TBAC caused α₂u-globulin accumulation in male rat kidneys from all exposure groups and increased liver weights in 1600 ppm rats and mice. Levels of thyroxin were decreased in male mice exposed to 1600 ppm TBAC for 4 weeks but otherwise thyroid endpoints were unaffected in rats and mice at either the 4 or 13 weeks time points. There was no evidence or immunotoxicity or reproductive toxicity in rats. Pregnant rats receiving 1000 mg kg⁻¹ d⁻¹ TBAC exhibited severe signs of acute neurotoxicity and decreased feed consumption and body weight gain. Fetal viability and growth were unaffected.