BACKGROUND: Aluminum is used widely in antiacid drugs, food packaging and additives. Aluminum chloride (AlCl3) was known to cause maternal toxicity and embryo lethality. OBJECTIVES: The aim of this study is to assess the effect of maternal administration of aluminum chloride during the period of organogenesis on the developing fetus. MATERIAL AND METHODS: Fifty eight pregnant female albino rats (weighing between 180-200 gm) were used in this study. The pregnant females were divided into 2 groups (control and treated). The treated group was given 330mg/kg/b.wt. of Alcl3 dissolved in distilled water intragastrically from the 6th to the 15th day of gestation. Pregnancies were interrupted by sacrifice at the 20th day of gestation and the obtained fetuses were examined for any gross external abnormalities then the fetuses obtained from both groups were classified into three subgroups. In the first two subgroups, the fetuses were prepared separately and examined for skeletal and visceral abnormalities under stereoscope microscope. From the third subgroup, tissue specimens were obtained from the placenta and brain of the fetuses and prepared by the light microscope and the immunohistochemical technique (for the brain) and analyzing the results morphometrically and statistically. RESULTS: Results of this study revealed external morphological findings in the form of reduction in the implantation percentage, increase in the number of fetal resorption and dead fetuses, decrease in the mean fetal body weight and placental weight; decrease the fetal crown rump (C.R) length, subcutaneous haemorrhage and growth retardation in fetuses obtained from the treated mothers compared to those obtained from the control mothers. Also there were visceral malformations in the form of dilated nasal cavity, anophthalmia, shrunken brain and intrathoracic haemorrhage. Skeletal malformations recorded in this study were in the form of incomplete ossification of some bones of the skull and vertebrae, deformed ribs and absence of phalanges in the fore and hindlimbs.