This chapter provides detail description of respiration. Causes and effects of Chest cage variations, functions of upper respiratory tract, added sounds, pneumonia, pleural effusion, mediastinal lesions, diaphragmatic paralysis, respiratory functions and sputum examination are given in detail. 7 tables are included to highlight difference between hemoptysis and hematemesis, difference between tympanic note and resonance difference between crepitation and pulmonary rub, difference between obstructive airway disease and restrictive airway disease, difference between parietal pleura and visceral pleura.