Dengue cases are often underreported in most hospitals and health centres, and are often not diagnosed as dengue, because their symptoms overlap with many other diseases. This study aimed to determine the knowledge of Physicians in health centers of Riyadh, the study is a cross-sectional descriptive study conducted on a group of Physicians and workers in health centers in the city of Riyadh, who provide medical consultations and health care in health centers. They number (253) individuals, including Physicians and practitioners in infectious diseases and internal medicine, and a number of nurses and midwives. The results showed that dengue fever is not well known among many health care workers, whether Physicians or nurses.