Cyclohexanone was evaluated for reproductive toxicity in CD Sprague-Dawley albino rats (30 rats/sex/generation/concentration group) receiving whole-body exposure to vapor concentrations of 0, 250, 500, or 1000 (F0 generation)/1400 (F1 generation) ppm for 6 hours/day through 2 consecutive generations. F0 adults were exposed 5 days/week for a 10 week pre-mating treatment period. During the 15 day mating period, males and females were exposed 5 and 7 days/week, respectively. Following mating, females were exposed 7 days/week on gestation days 0-20 and on lactation days 5-28. Males continued to be treated 5 days/week post-mating until sacrifice. F1 adults were exposed 5 days/week for 12-15 weeks prior to mating. Exposure of F1 animals during mating, gestation, and lactation was similar to that for the F0 animals. Treatment had no adverse effects with respect to growth or reproductive performance of F0 adults, or F1 fetal or offspring development. High-concentration F1 adults had clinical signs of toxicity. decreased survival rates, male body weights and fertility, and progeny (F2 generation) with decreased survival rates and body weights. To determine if the decrease in fertility was reversible, high-concnetration males F1 rats were rested for 2 days following the last exposure, then paired weekly with 2 females for 4 consecutive weeks, rested 1 week, bred the 6th week, rested the 7th, and bred the 8th week post-treatment. The fertility of high-concentration male F1 rats during the post- treatment period was normal, indicating that treatment-related depressions in fertility were reversible.