The aim of this study to investigate the possible developmental toxicity and teratogenicity of enrofloxacin on maternally-treated chick. Four equal fertile egg groups were utilized in the present study. The first (control) group was obtained from chickens that did not receive any antibacterial medication, while the second, third and fourth ones were collected at the first, seventh and tenth days following chicken treatment with enrofloxacin (10%) for 7 consecutive days, respectively. On embryonic days 6½ and 13, embryos were evaluated for mortality rate, fresh body weight, crown-rump length, anterior-posterior head length and various morphological and skeletal changes. The results revealed that 6½ and 13-day-old embryos of eggs obtained on both the first and seventh days following chicken treatment with enrofloxacin exhibited significantly (p<0.05, versus controls) similar reductions in the means of fresh body weight, crown-rump length and anterior-posterior head length. Also, the embryos exhibited significant incidence of mortality, oedemas formation, omphalocele, structural anomalies in the head and limbs as well as delay of cartilage and bone formation. Moreover, eggs opened on embryonic day 6½ showed weakly ingested yolks, uneven yolk sac appearance and poorly developed vitelline circulation. However, the changes of these parameters in embryos of eggs collected on day ten following chicken treatment with enrofloxacin were infrequent (in comparison with those of controls). These data recommend avoiding usage of chicken eggs (for reproducing or human consumption) for at least ten days following chicken treatment with enrofloxacin against infectious diseases. Also, emphasizes on respecting the withdrawal times for drugs according to the maximum residual limits established by the regulatory agencies.