This chapter gives laboratory approach to bleeding disorders. It also gives the general principle of clotting tests, detailed method for preparation and standardization of laboratory reagents for coagulation tests and their optimal storage procedure. It gives detailed methodology for performing bleeding time, Activated Partial Thromboplastin Time (APTT), Prothrombin Time (PT), Clot stability/solubility Test, thrombin time, fibrinogen assay, D dimer estimation and mixing tests. It also gives detailed methodology for Russell Viper Venom time, prothrombin consumption index, one stage F VIII assay, and screening for F VIII inhibitor and method for quantitation of F VIII inhibitor. It gives detailed methodology of platelet aggregation studies and tests for von-Willebrand’s disease. It also gives a few case studies pertaining to bleeding disorders.