•In clinical practice, a substantial proportion of platelet transfusions are routinely administered outside the guidelines.•Unnecessary platelet transfusions are an unjustified extra burden on a scarce healthcare resource and may also be detrimental to the patients.•One-third of all PLT transfusions were inappropriate mainly because of transfusions above the recommended threshold and unjustified double units transfusions. Hematology patients are intensive platelet users. In clinical practice, a substantial proportion of platelet (PLT) transfusions are routinely administered outside the guidelines despite compelling evidence for recommendations. Those unnecessary PLT transfusions are an unjustified extra burden on a scarce healthcare resource and may also be detrimental to the patients. This study aims to evaluate indications and assess the appropriateness of PLT transfusion, as well as to identify common discrepancies and propose modalities for better compliance with guidelines. The audit of all PLT orders for adult hematological inpatients was conducted over 2 months. The assessment was performed using guidelines for PLT transfusion. Patient demographic, clinical, and transfusion data were collected from hospital electronic medical records. Based on 286 PLT orders, 344 PCs were transfused to 67 patients: 235 (82.2%) prophylactical due to low PLT count, 34 (11.9%) preprocedural and 17 (5.9%) therapeutic. Overall, 105 (36.77%) PLT transfusions were inappropriate: 78 (33.2%) of all prophylactic PLT transfusions due to low PLT count, 17 (50%) off all preprocedural and 10 (58.8%) of all therapeutical transfusion. The major reason for PLT transfusion inappropriateness was transfusion above the recommended threshold. Double units of PCs were transfused in 36.7% of all PLT transfusions and 32.4% of them were considered inappropriate. Our audit of PLT transfusion practice found a large proportion of inappropriate PLT transfusions. Based on the most common deviations from the guidelines a variety of targeted measures for improvement are proposed.