Purpose: Megacystis Microcolon Intestinal Hypoperistalsis Syndrome (MMIHS) is a congenital disease, and the etiology. of the disease is unclear. It is speculated that maternal ingestion of some drugs during pregnancy may be an etiologic "factor. In this study we aimed to investigate the effect of maternal ingestion of ethanol on the fetal bladder and colon in pregnant rats. Methods: We separated animals into an ethanol group including 30 rats and a control group with 14 rats. Nothing was given to the control group during pregnancy. Orogastrically 2 cc/day 30% ethanol was given to the study group from the 6th to I 2th day of pregnancy. All of them were sacrified on the 20th day of pregnancy. Histopathological examination of the fetal colon and bladder was performed. Results: In the ethanol group a significant decrease in the colon and bladder diameter, a significant decrease in the thickness of the colon and bladder wall, an increase in vacuolar degeneration in the muscles of the bladder wall, an increase in connective tissue proliferation among the muscles of the bladder, a significant decrease in the number of ganglion cells in the myenteric plexus of the colon and a significant decrease in the thickness of the bladder tunica muscularis were determined. Conclusion: In our rat model we found histological structural changes in the rats’ colon and bladder wall similar to a pathological finding found in some of the MMIHS patients’ bowel and bladder as a result of using ethanol on the 6th-12th days of pregnancy.