This chapter discusses about various techniques for the study of pathology. Surgical pathology is the classic and time-tested method of tissue diagnosis made on gross and microscopic study of tissues. The surgical pathology protocols include request forms, tissue accession, gross room and histopathology laboratory. Majority of histopathology departments use automated tissue processors having 12 separate stages completing the cycle in about 18 hours by overnight schedule. The ideal surgical pathology report must contain history, precise gross description, brief microscopic findings and morphologic diagnosis. Enzyme histochemical techniques require fresh tissues for cryostat section and cannot be applied to paraffin-embedded sections or formalin-fixed tissues since enzymes are damaged rapidly. The usual type of microscope used in clinical laboratories is called light microscope. Polarising microscope is used for demonstration of birefringence e. g. amyloid, foreign body, hair etc. Immunofluorescence technique is employed to localise antigenic molecules on the cells by microscopic examination. Electron microscopy is applied in renal pathology, ultrastructure of tumours of uncertain histogenesis, subcellular study of macrophages in storage diseases and research purposes. Immunohistochemistry (IHC) is the application of immunologic techniques to the cellular pathology. Diagnostic molecular pathology detects abnormalities at the level of DNA or RNA of the cell. Flow cytometry is a modern tool used for the study of properties of cells suspended in a single moving stream.