This chapter reviews common respiratory disease processes. It provides an overview of the disorders that may be met by the thoracic anesthetist, and considers their anesthetic implications. Infective disorder described in the chapter includes pneumonia, tuberculosis, aspergillus, bronchiectasis, and cystic fibrosis. Patients with pneumonia may present with a history of cough, production of purulent sputum and fever, together with pleuritic chest pain and shortness of breath. Hematogenous spread causes generalization of the disease and can cause miliary tuberculosis (TB) and/or TB meningitis. The chapter discusses airway obstructive disorders such as asthma and chronic obstructive pulmonary disease (COPD), along with interstitial lung disease and the disease involving the pulmonary circulation. Pulmonary embolism usually occurs as a complication and consequence of deep vein thrombosis. Lung cancer remains the commonest cause of cancer death worldwide.