Cytomegalovirus (CMV) pneumonia can be a life-threatening disease in immunocompromised patients such as transplant recipients and patients given immunosuppressive therapy. Although CMV infections are highly prevalent in the general population, symptomatic pneumonia in an immunocompetent adult has been documented rarely. We describe a 47-year-old male smoker who presented with a 3.5-cm cavitary mass in the upper lobe of the left lung, highly suggestive of lung cancer. Wedge resection of the mass on thoracotomy revealed CMV pneumonia with no evidence of malignancy or other infections. No antiviral therapy was given to this immunocompetent patient, and no additional manifestations of CMV disease occurred.