Retinoic acid and some selected analogs were tested to evaluate their effect on skin morphogenesis and toxicity in the chick embryo. Retinoids dissolved in dimethyl sulfoxide were injected at doses varying from 10 pmol to 10 μmol into the amniotic cavity of 10-day-old chick embryos (n = 20). At 16 days of incubation, the eggs were opened to record the number of dead embryos and the number of embryos presenting club-shaped feathers. A lethal embryotoxic dose (LED50d16) which, at 16 days of incubation, provokes the death of 50% of the embryos and an effective dose (ED50) which induces production of club-shaped feathers in 50% of surviving embryos were then calculated using log-probit analysis. Retinoids could be classified according to their ED50. For example, arotinoid Ro 13–7410 appears approximatly 1,000 times more active than all transretinoic acid. However, the analogs which are more active are also more toxic. The assay described in the present study appears to be a simple and useful model for the screening of retinoids.