Prof. Al-Hajjaj, graduated from King Saud University Medical College in 1981 and obtained The American board of Internal Medicine in 1986, Certificate of Fellow of the Royal College of Physician and Surgeons of Canada( FRCP (C ) in 1987 and The American Board of Respiratory Diseases in 1988. He has been a Professor of Medicine and Pulmonology since 2002. His research interest is in the field of bronchial asthma and COPD.Professor Al-Hajjaj has published more than 40 research papers in the medical literature. Currently he is the head of Respiratory Division, in the Medicine Department, College of Medicine, King Saud University, and The chairman of the Saudi Thoracic Society.