Background : Chronic fatigue syndrome (CFS) places considerable burdens on patients and society. This study assesses family physicians’ awareness of CFS. Methods: Between November 11 and December 29, 2016, a cross–sectional study was performed with trainees of the Ministry of Health Family Medicine Post–Graduate Program in the Eastern Province of Saudi Arabia. All trainees were invited to participate through a validated, piloted internet–based questionnaire. Results: Seventy trainees completed the 19–item questionnaire (response rate=95.89%). The construct validity achieved an “excellent” rating, and the reliability had a Cronbach‘s alpha of 0.61. The mean scores were as follows: Knowledge=81%, Perception=78.34%, Attitude=69.77%, Belief=77.71%, and Awareness=72.22%. Four (5.7%) trainees had diagnosed CFS. Seventeen trainees (24.3%) disagreed that CFS was a distinct disease, 23 (32.8%) agreed, and 30 (42.9%) were undecided. The female trainees had higher Perception scores than the males (p=0.019). Conclusions: The overall Awareness score was “moderate”, whereas the lowest score was found for Attitude, which involves the conjoining of CFS and depression by the physicians. The trainees were unprepared to diagnose CFS; even trainees who had diagnosed CFS previously did not have a high level of awareness.