The embryotoxicity and teratogenicity of nitrobenzene were evaluated in mated female New Zealand White rabbits (22/group) exposed by inhalation to nitrobenzene at nominal concentrations of 0, 10, 40 or 100 ppm for 6 hrs/day during gestation days (GD) 7-19. The animals were sacrificed on the day evidence was observed that they aborted or delivered prematurely or on GD 30, whichever occurred sooner. Significant differences between treated and control animals were observed in the following: increased absolute and relative liver weight and methemoglobin values (mid- and high-dose groups). No significant differences between treated and control animals were observed in the following: mortality, pregnancy, abortion or premature delivery rates, body weights, corpora lutea and uterine implantation data, fetal weight, crown-rump distance, fetal sex distribution, and external, visceral and skeletal evaluation of fetuses.