1,1,1‐Trichloro‐2‐propanone (1,1,1‐TCP) has been identified as a chlorination by‐product in finished drinking water supplies. Since little was known of its oral toxicity, exposure studies were conducted with male and female Sprague‐Dawley rats (10 males and 10 females/group) exposed by corn oil gavage at 0, 16, 48, 161, or 483 mg/kg for 10 d or 0, 30, 90, or 270 mg/kg for 90 d. Evaluations included mortality, clinical signs, body weight, food consumption, ophthalmology, hematology, clinical chemistry, urinalysis, organ weights, gross pathology, and histopathology.