Abstract The therapeutic effects of the immunosuppressive agent, cladribine, have been demonstrated by its toxicity to cells. However, its effects on healthy cells of the body is poorly understood. The aim of study was, hence, to, firstly, evaluate the morphology of the endocrine and exocrine pancreas after the administration of cladribine according to the "leukemic" schema, and, secondly, to assess its impact on the intensity of apoptosis. The experiment was carried out on female Wistar rats which were placed within the control group KA, and the experimental groups: A and A-bis. In the experimental groups, Cladribine was administered according to the cycle used to treat human hairy cell leukemia. In group A, the material was taken 24 hours after administration of the last dose of the drug, while in group A-bis, this was done after a 4 weeks break. The reaction was assessed to be average in 80% of all cells in group A, and in 64% of all acinar cells in group KA, while in group A-bis, the majority of the exocrine cells demonstrated a lack of immunohistochemical response (72%). Moreover, most endocrine cells (60%) in group A-bis revealed a strong reaction, while in Group A, the corresponding figure is a little over 34%. A comparison of the severity of the caspase 3 expression in both the exocrine and endocrine pancreas showed significant differentiation results between the group KA and group A-bis, and between group A and A-bis (p < 0.0001). In can be concluded that endocrine cells are more sensitive to cladribine than are exocrine cells.