Hemogram is the commonest investigation asked for by the clinician. It plays an important role in diagnosis of underlying disorders. Hence it is important to ensure that there are minimal pre analytical and analytical variables in performing hemogram. This chapter outlines detailed methodology for hemogram tests and mentions the appropriate sample collection in anticoagulants. Difference between capillary and venous blood sample are highlighted. The methods for Hemoglobin determination include cyanmethemoglobin method for hemoglobin estimation, manual methods for estimation of TLC and platelet count, along with detailed methodology for micro-hematocrit and reticulocyte count estimation. Platelet count manually is still required in some situations like high platelet anisocytosis (giant platelets) when automated cell counters invariably give erroneous platelet count. Peripheral Blood Smear examination is an important part of hematologic evaluation. Correct methodology for preparation of blood smear and its staining and examination are given. Changes in RBC and leucocytes in various diseases are also highlighted. Method of blood cell counting by electronic counter and their maintenance schedule is mentioned.