The effect of inhaled chloroform on embryonal and fetal development was evaluated in CF-1 mice. Bred mice were exposed to 0 or 100 ppm of chloroform for 7 hr/day from Days 1 through 7, 6 through 15, or 8 through 15 of gestation. Exposure to chloroform from Days 1 through 7 or 6 through 15 significantly impaired the ability of the female rats to maintain pregnancy but was not significantly teratogenic. In comparison, a significant increase in the incidence of cleft palate was observed among the offspring of mice inhaling chloroform from Days 8 through 15 of gestation, but no effect on the ability of the female rats to maintain pregnancy was discerned. Other signs of toxicity observed among the litters of mice exposed to chloroform included: decreased ossification of bones (all experimental groups), decreased incidence of resorptions (Days 1 through 7), and reduced fetal body measurements (Days 1 through 7 and 8 through 15).