Respiratory disorder is a term that encompasses a variety of pathogenic conditions that affect respiration in living organisms. Respiration makes gas exchange possible in higher organisms. The gas exchange involves taking oxygen into the body and expelling carbon dioxide. Respiratory disease occurs in the respiratory tract, which includes the alveoli, bronchi, bronchioles, pleura, pleural cavity, trachea and the nerves and muscles of breathing. This chapter covers the disorders of upper respiratory tract, foreign body aspiration, cystic fibrosis, pleural effusion, and lung abscess. Cystic fibrosis (CF) is an autosomal recessive genetic disorder that affects multisystem mostly the lungs but also the pancreas, liver, and intestine. CF is an inherited disease of the mucus and sweat glands. It affects mostly your lungs, pancreas, liver, intestines, sinuses and sex organs. Pleural effusion, which in pediatric patients most commonly results from an infection, is an abnormal collection of fluid in the pleural space.