The fungicide dinocap is currently used in the control of powdery mildew. The authors have reported that dinocap is teratogenic in the CD-1 mouse, causing cleft palate, otolith defects, and fetal weight deficits well below maternotoxic dose levels. In the study the maternal and fetal toxicity of dinocap was determined in the Sprague-Dawley rat and Syrian golden hamster, and Adult-to-Developmental (A/D) toxicity ratios were calculated and compared to the previously established A/D ratio of dinocap in the mouse. The A/D ratios for dinocap in the rat and hamster are similar, and are approximately one. These previous studies have demonstrated that dinocap is teratogenic in the mouse, with an A/D ratio in the range of 8-16 in the species. The basis for the species-specific teratogenicity and inconsistent A/D ratio of dinocap is unknown.