Background and Objectives: The socioeconomic working group of the European myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) Research Network (EUROMENE) has conducted a review of the literature pertaining to GPs' knowledge and understanding of ME/CFS; Materials and Methods: A MEDLINE search was carried out. The papers identified were reviewed following the synthesis without meta-analysis (SWiM) methodology, and were classified according to the focus of the enquiry (patients, GPs, database and medical record studies, evaluation of a training programme, and overview papers), and whether they were quantitative or qualitative in nature; Results: Thirty-three papers were identified in the MEDLINE search. The quantitative surveys of GPs demonstrated that a third to a half of all GPs did not accept ME/CFS as a genuine clinical entity and, even when they did, they lacked confidence in diagnosing or managing it. It should be noted, though, that these papers were mostly from the United Kingdom. Patient surveys indicated that a similar proportion of patients was dissatisfied with the primary medical care they had received. These findings were consistent with the findings of the qualitative studies that were examined, and have changed little over several decades; Conclusions: Disbelief and lack of knowledge and understanding of ME/CFS among GPs is widespread, and the resultant diagnostic delays constitute a risk factor for severe and prolonged disease. Failure to diagnose ME/CFS renders problematic attempts to determine its prevalence, and hence its economic impact.