Sputum is an important diagnostic tool for diagnosis of tuberculosis, malignances and other inflammatory conditions, etc. Collection of sputum sample, types of examination including physical and microscopic, preparation of sputum for AFB and malignant cells, principles of staining of AFB and results of AFB positive smear are described. The most important global infectious disease-Tuberculosis, its etiopathogenesis, types, important diagnostic tests done, importance of PCR in diagnosis of tuberculosis and brief discussion on typical and atypical tuberculosis are incorporated. Definition of granuloma, causes of granulomatous inflammation, Mantoux test with its procedure and interpretation are also discussed.