The purpose of this study was to investigate for the first time the prevalence and pathology of spontaneous atherosclerosis in free – living pigeons in Mosul, Iraq. A hundred apparently healthy, 1-1.5 year old both sexes pigeons of local breed free – living used. Effects of factors such as weight, sex, age and health status on prevalence of the condition were also studied. Prevalence of naturally occurring atherosclerosis was 10%. Grossly, the heart was hypertrophied and of firm consistency, aorta and coronary arteries were prominent and cordlike with thickened walls. Microscopically, lipid – laden "foam cells" were seen throughout the thickened tunica media and intima. Damage of the elastic lamellae and hypertrophy of the smooth muscle cells were also noted. Spontaneous atherosclerosis occurred more frequently in old pigeons. No effect was found for sex, weight, and health status of the pigeons on prevalence and pathology of spontaneous atherosclerosis. It was concluded that spontaneous atherosclerosis is fairly common in local pigeons and it occurred more commonly in old pigeons. Sex, weight, and health status of the pigeons did not constitute risk factors for the occurrence of spontaneous atherosclerosis.

Key words: Atherosclerosis; Free Living; Iraq; Mosul; Pigeons; Spontaneous