A two- generation reproductive toxicity study was conducted with groups of 30 female and 30 male Fischer 344 rats exposed by inhalation to methylene chloride vapors at concentrations (measured by an infrared spectrometer) of 0, 100, 500 or 1500 ppm for 6 h/d, 5 d/week. These concentrations had previously been shown to cause treatment- related effects in 2-year studies. The F0 rats were exposed from approximately 7 weeks of age for 14 weeks and were mated with another rat from the same exposure group. Groups of 30 female and 30 male F1 animals were exposed from 4 weeks of age (after weaning) for 17 weeks and were similarly mated. Exposure for both F0 and F1 animals was conducted 7 d/week during mating, gestation and lactation, however dams were not exposed from gestation- day 21 through the fourth day post-partum. Adult rats were exposed to the test material from weaning of their young until sacrifice for an unspecified length of time. Clinical and necropsy observations of F0 and F1 animals included no treatment-related effects on demeanor, physical appearance, body weight, fertility and gestation survival indices, litter size, pup weights, or histopathology. No data was given on the F2 generation.