In this study, various types of fetal malformations, including cleft palate were induced by the intraperitoneal administration of cyclophosphamide to pregnant mice. The dose 75 mg/kg b.w. when given at the 12th day of gestation has lead to multiple defects including cleft palate, flat head, curved head, exencephaly, shortening of the extermities, and smaller size of the fetus. When the same dose was given at the 13th day of gestation, the malformations included curved head, exencephaly, shortening of the extermities and a lower percentage of cleft palate. When given at the 14th, 15th, or 16th days of gestation, it lead to curving of the head and small size of the fetus. Cleft palate was confirmed histologically as the palatine shelves were quite apart. Additionally, there were thickening and vacuolar degeneration of the epithelial element of the shelves. The core of the shelve consisted of pleomorphic mesenchymal cells with foci of chondroblastic proliferation.