Cytomegalovirus (CMV) infection can present with severe manifestations that are associated with significant morbidity and mortality, especially in immunocompromised patients. CMV infections in immunocompetent patients are usually transient and do not exhibit many symptoms. However, in some patients, the manifestations can be severe. We report CMV colitis in two immunocompetent patients; one in a young man who was critically ill with septicaemia and significant non-bloody diarrhoea that responded to specific CMV treatment, and another in an elderly woman who presented with nonspecific abdominal pain and fever that resolved without specific CMV treatment.