Background: Laboratory reports play major role in patient management. So, more importance should be given to the quality of laboratory reports. Hematology laboratory must ensure reliable test results with high degree of precision and accuracy. Even after so many advances, pre-analytical errors remain a challenge for hematology laboratory. Aims And Objectives: The present study was undertaken with an objective to identify the major reasons of sample rejection in the pre-analytical phase and to do a root-causeanalysis of that reasons in order to improve the quality of laboratory services and proper patient care.