Histopathology, cytology and frozen section are three important diagnostic tools in tissue and cellular pathology. These are very important to differentiate malignant, benign and inflammatory conditions and proper diagnosis for better management of diseases. All surgical specimens must come for histopathology diagnosis and any body fluid, scrapping, shedding of normal cells, discharge must come for cytological examination. Frozen section is very important to differentiate difficult suspicious malignant lesions, congenital anomaly like Hirschsprung disease and for IHC. In this chapter, Biopsy, its types, indication, routine processing H and E stain, fixatives used are described. Also cytology procedure, Paps staining, indication, fixatives are mentioned. Finally frozen section, its importance, indication and interpretation of result are also described.