Abstract: A Haemogregarine sp. infecting the Viper Cerastes cerastes gasperitti (35%) from K.S.A. was recorded for the 1st time. Parasites were recorded exclusively in the red blood cells of the Vipers. Erythrocytic parasites measured 17.5x3 μm with a nucleus of 8.1x2.5 μm. Mature Schizonts of 30x2.5 μm and producing 18-30 merozoites by ectomerogony were reported in the endothelial cells of blood capillaries of different internal organs (liver, spleen and lung). The merozoites measured 13x3.5 μm and these were similar to the stages in the red blood cells. The motile stages of the parasite recorded in the present study showed all the general architectures of the Apicomplexa with some pecularities such as presence of micronemes and rhoptries at both sides of the nucleus and the occrance of large number of subpellicular microtubules (80-90) extending to the posterior end of the parasite.