The causes of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are currently unknown, however viruses have been implicated. The absence of well-designed studies has hindered the understanding of this disease and the aim of this review was to discuss the literature regarding viruses and ME/CFS. Several viruses were discussed including the herpes virus, which is responsible for illnesses such as chicken pox and cold sores. This virus has not always been associated with the onset of ME/CFS, however it may be in certain individuals. The enteroviruses, which are responsible for illnesses such as hand, foot and mouth and polio, were also reviewed and it was concluded that it is unlikely that these have a role in ME/CFS. Several other viruses were also discussed. The authors then went on to describe how these viruses can affect human cells, potentially causing ME/CFS. It was concluded that the data available is controversial and only certain individuals may be affected, better studies are required. This study could be used by healthcare professionals to identify individuals at risk of ME/CFS following viral infection and understanding how ME/CFS may develop.