Introduction: The present study was carried out to evaluate the effect of the non-steroidal anti-inflammatory drug diclofenac sodium (DS) on the fetuses of albino mice from the morphological and skeletal points of view.   Material and methods: Sixty adult pregnant female mice were used in the present study. They were allocated into 6 groups (10 mice each). The first two groups served as control and were injected intraperitoneally (i.p.) with the solvent of the drug, and the 3^rd and 5th   groups were treated with 1.5 and 3mg/kg body weight of diclofenac sodium for 6 days ( gestation days 1-6 ), respectively ; the 4^th  and 6^th  groups were treated with 1.5and 3mg/kg body weight  of the drug  for 8 days ( gestation days 7-14), respectively.   Results: The morphological examination of the fetuses of treated groups showed conspicuous decrease in the average body weight and body length in all treated groups. The fetuses maternally treated with the drug showed noticeable external morphological malformations and their skeletons exhibited mild retardation in skeletal elements.   In conclusion: The non-steroidal anti-inflammatory drug diclofenac sodium had exerted marked morphological malformations and mild skeletal alterations in mice fetuses maternally treated during different periods of gestation.   Introduction: The present study was carried out to evaluate the effect of the non-steroidal anti-inflammatory drug diclofenac sodium (DS) on the fetuses of albino mice from the morphological and skeletal points of view.   Material and methods: Sixty adult pregnant female mice were used in the present study. They were allocated into 6 groups (10 mice each). The first two groups served as control and were injected intraperitoneally (i.p.) with the solvent of the drug, and the 3^rd and 5th   groups were treated with 1.5 and 3mg/kg body weight of diclofenac sodium for 6 days ( gestation days 1-6 ), respectively ; the 4^th  and 6^th  groups were treated with 1.5and 3mg/kg body weight  of the drug  for 8 days ( gestation days 7-14), respectively.   Results: The morphological examination of the fetuses of treated groups showed conspicuous decrease in the average body weight and body length in all treated groups. The fetuses maternally treated with the drug showed noticeable external morphological malformations and their skeletons exhibited mild retardation in skeletal elements.   In conclusion: The non-steroidal anti-inflammatory drug diclofenac sodium had exerted marked morphological malformations and mild skeletal alterations in mice fetuses maternally treated during different periods of gestation.