Akbalik ME, Erdogan S, Saruhan BG, Sagsoz H. The distrubution of immune system cells in bursa of Fabricius of partridge (Alectoris chukar). Aim: The bursa of Fabricius is a primary lymphoid organ restricted to birds that is responsible for the proliferation and differentiation of B lymphocyte precursors within its follicular structure. In the process of creating a functional B lymphocyte, the cells acquire the necessary receptor property to recognize the antigen, major histocompatibility complex and adhesion molecules in this organ. The purpose of this study is to determine the localization and distribution of CD8, CD68, MHC-I and II-positive cells in bursa of Fabricius of partridge. Materials and Methods: In this study, some immune cells localization in bursa of Fabricius of 10 adult chukar partridge (5 male and 5 female) were examined on the level of light microscope by using immunohistochemical methods.Results: It was revealed that in general CD8, CD68, MHC-I and II-positive cells were localized in lamina propria and cortex and medulla of lymph follicles. In contrast, no immunoreactivity was observed in the muscle layer.Conclusion: The expression of these factors playing a role in immune response is thought to provide contribution for immunological studies in avian species