Diagnostic cytology pertains to the interpretation of cells from the human body that either exfoliate (desquamate) spontaneously from epithelial surfaces, or the cells are obtained from various organs/tissues by different clinical procedures. Diagnostic cytology helps in diagnosis and management of cancer, identification of benign neoplasms, intraoperative pathologic diagnosis, diagnosis of specific infections, assessment of hormonal status in women and identification of cell of origin. Diagnostic cytology is divided into exfoliative cytology and interventional cytology. The fully-developed invasive squamous cell carcinoma of the uterine cervix is preceded by a pre-invasive intraepithelial neoplastic process that is recognisable on histologic and cytologic examination. Lesions in the oral cavity may be sampled by scraping the surface with wooden and metal tongue-depressors. For the oesophagus and stomach, samples are obtained under direct vision by brushing or lavage through fibreoptic endoscopes. Papillary tumors of low-grade are lined by urothelium showing no morphological abnormalities or only slight cellular and nuclear abnormalities. Interventional cytology is virtually synonymous with Fine Needle Aspiration Cytology and is increasingly being used to sample a wide variety of body tissues. FNAC is most often used for diagnosis of palpable mass lesions. Palpable lesions commonly sampled are breast masses, enlarged lymph nodes, enlarged thyroid and superficial soft tissue masses.