Abstract: Two splenectomized sheep were infected respectively with Theileria luwenshuni and T. uilenbergi, 2 spec-ies identified by PCR. When piroplasms were found in blood smears from ears of the sheep, morphological observation on the Theileria spp. was carried out by optical microscopy. By Giemsa staining, the cytoplasm exhibited in slight blue and nucleus in purple. The two Theileria species displayed various shapes, but pyriform-shaped, round-shaped and needle-shap-ed parasites appeared in every stage of the infection. In fact, there is no significant morphological difference between the two species.

Key words: Theileria luwenshuni, Theileria uilenbergi, Morphology