OBJECTIVE: To assess the effect of experimental liver damage in rats on bone marrow megakaryocytes. STUDY DESIGN: Repeatable and complementary models of liver damage were obtained by surgical bile duct ligation (Group 1, n=8). Group 2 (n=6) consisted of sham operated animals. Group 3 (n=6) included animals not exposed to any factors that could affect their health. Bone marrow slides, stained with hematoxylin and eosin and exposed to CD61 antibody and factor VIII, were examined, and cytomorphometric parameters of megakaryocyte as well as their location in relation to the vascular structures were assessed. RESULTS: Comparative analysis of the microscopic slides of the bone marrow obtained from each group revealed a number of features indicating low-activity forms of megakaryocyte in the study group. The following changes were statistically significant (p < 0.05): Decreased surface area of the cell and megakaryocyte circumference, reduced cell shape coefficient, decreased surface area of the cell nucleus, decreased cell nucleus circumference and nucleus/cytoplasm ratio, and an increased nucleus shape coefficient. CONCLUSION: Our findings confirm the effect of liver damage on the bone marrow megakaryocyte line. Our findings confirm the suppressive effect of liver damage on the development and maturation of the megakaryocyte line. However, there were no corresponding changes in the platelet count measured in the collected blood. Changes observed in the cytomorphometric parameters of megakaryocytes seem to precede the thrombocytopenia described in literature. © Science Printers and Publishers, Inc.