This chapter describes hematocrit, ESR estimation and peripheral blood smear examination. Hematocrit (packed cell volume) is the ratio of the volume of red cells to that of the whole blood. It indicates relative volume of red cells and plasma (e.g. in anemia red cells are reduced with corresponding reduction in the hematocrit). Erythrocyte sedimentation rate (ESR) estimation is a commonly used nonspecific test in routine clinical practice. Peripheral smear (peripheral blood film) is the most important, valuable and frequently asked investigation in hematology laboratory. This chapter also covers the stains for blood smear, preparation of the peripheral blood smear, fixation of the smear, and staining of the smear.