The present study describes the developmental stages of Haemogregarina species in the blood and tissues of naturally infecting white-spotted gecko Tarentola annularis collected from Qena, Egypt. Different parasite's forms were observed infecting the erythrocytes. The gamonts enclosed within parasitophorous vacuole and seems to have no clear effect on the
host cell especially in case of immature parasite forms. But in the presence of mature gamonts the host cell nucleus displaced. The parasitaemia level is up to 280 per 10,000 erythrocytes counted. Trophozoites and gamonts have been recognized in the blood smears. The rounded trophozoite diameter is 3.84±0.87 μm, while the elongated trophozoite measured 4.42±0.69×2.8±0.56 μm. The mature gamonts were differentiated into two forms; short gamont measuring 10.82±0.82×3.30±0.73 μm (range: 10-12.1×2.2-4.4 μm) and the long gamont measured 14.67±0.83×3.96±0.77 μm (range: 14.1-16.5×3.3-5.5 μm). Merogony carried out only in the endothelial cells of the blood capillaries in the lung. Different merogonic stages have been recognized and differentiated in two forms; micromeront measured 13.250.50×120.0 μm and produces a few number of large merozoites, macromeront measured 19.750.87×13.250.50 μm and produces more small sized merozoites. The gamonts and merozoites have the general characteristic ultrastructures of the Apicomplexa containing components of the apical complex, e.g. pellicle, micronemes, rhoptries, and few dense bodies and subpellicular microtubules.