Clarithromycin, a new macrolide antibiotic, is effective in the management of a wide range of clinical problems including outpatient treatment of community-acquired pneumonia, shortening the course of peptic ulcer disease associated with Helicobacter pylori infection and curing previously resistant respiratory infections in immune-compromised patients. The present study is planned to study the effect of clarithromycin on the pregnant female rats and their fetuses during the last gestational period stage. This study includes the effect of clarithromycin on therate of abortion, malformation of fetuses, skeletal, histological changes and DNA fragmentation of liver cells of pregnant rats and their fetuses. In the present study two groups of pregnant animals were used. The first group received distilled water from 15^th to 19^th days of gestation and used as control and sacrificed at 20^th day of gestation. The other group is orally administered with 45mg/kgclarithromycin from 15^th to 19^th days and sacrifices at 20^th day of gestation (the therapeutic dose). The obtained results showed a significant decrease in maternal body weight gain and increase in the rate of abortion, resorption and growth retardation of fetuses.Fetuses of the treated group showed severe lack of ossification on the skull bones, phalanges and sternum bone as well as shortness in the ulna and radius bones. Histological studies of pregnant rats revealed congestion and dilatation of the central vein of the liver lobules and fatty degeneration of the hepatocytes with severe DNA fragmentation.In 20 day-fetuses, there were a marked increase of necrotic hepatocytes associated with increased average of megakaryocytes and periportal leukocytic infiltration.