Background & Objectives: Platelet transfusion reduces mortality from hemorrhage in patients with  thrombocytopenia. Platelet transfusions are given prophylactically or therapeutically for managing patient with  various platelet consumptive or destructive disorders. This study evaluates the effect of platelet transfusion over  the count and parameters of platelets. The objective of this study is to compare the Platelet count, Mean Platelet  Volume (MPV) and Platelet Distribution Width (PDW) before and after platelet transfusion. Materials and Methods: The platelet parameters of 202 samples with thrombocytopenia, demographic variables  including gender, clinical details including indication for platelet transfusion, blood group, Platelet count, MPV,  PDW before and after transfusion and additional details such as critical illness, transfusion reaction, stay in ICU  etc, were noted. Descriptive statistics such as mean were calculated for descriptive variables such as difference in  platelet count, MPV, PDW before and after transfusion. Results: The rise in platelet count with one unit of platelets was approximately 40000/µL and that with 12 units  was 1,00,000/µL.The rise in MPV with one unit of platelets was approximately 2 fL and that with 12 units was  approximately 1 fL. The mean rise in PDW after platelet transfusion ranged from 1.2 to 1.8. Conclusion: Platelet count, MPV and PDW increase after platelet transfusion. The increase in platelet count is  disproportionate to the number of units transfused. Keywords: MPV, PDW, Platelet, Platelet count, Transfusion