AbstractThe Chernoff‐Kavlock assay was initially designed to identify developmental toxins within a relatively short time frame, using a mammalian system. Although it has been used for initial prioritization of multiple agents studied concurrently or for dosage‐range evaluations, it has not gained wide usage in a commercial setting. As proposed, use of the Chernoff‐Kavlock assay in an industrial setting is relatively inefficient, in terms of animal usage and data produced, when compared with available alternative study designs. Only a single dosage level was studied, and the data obtained from the assay do not provide sufficient information to meet the minimum requirements of safety evaluations submitted for regulatory review. For these reasons, other methods of prioritization are generally used. Alternate methods used for initial screening and prioritization at our laboratory are: (1) the hydra developmental toxicity assay; and (2) a dosage‐range study in rats. When the results of several pilot and definitive developmental toxicity assays performed in rats were compared, it appeared that the described pilot study served the dual functions of predicting and prioritizing the developmental hazard of the test agent and providing a dosage‐range study that identified the appropriate dosages to be tested in the definit