The aim of this study was to determine the histological changes of the thoracic aorta in rats fed on alcohol for a period of 24 weeks. Twenty male Wistar rats were divided into two groups. The ethanol group (n=10) was fed on a modified liquid diet (MLD) containing 7.2% ethanol for 24 weeks. The control group (n=10) was fed on MLD without ethanol throughout the experiment. At the end of the 24 weeks, the carotid arteries of the rats were cannulated and their blood pressures were measured. Ethanol levels measured by using the NAD+/NADH enzyme-spectrophotometric method. Rats were killed by decapitation. 3 mm long segments of thoracic aortae were fixed in 10% neutral buffered formalin and investigated by light microscope, following routine tissue processing and staining. In the ethanol group, rats had increased systolic and diastolic blood pressures. In the tunica intima, there was no evidence of any alcohol-induced effect that could indicate disruption, but some of the rats showed focal changes in their tunica media. The elastic lamellae of the media were degenerated and fragmented. The aorta wall was thicker in these areas. The tunica adventitia was normal and showed no differences from that of the controls. Our results revealed that chronic alcohol intake degenerates media architecture in the rat thoracic aorta, causes fragmentation of elastic lamellae and destroys the lamellar unit.