Cytomegalovirus (CMV) is an important cause of morbidity and mortality in immunosuppressed patients. Though acute lymphoblastic leukemia (ALL) is an immunosuppressed state, CMV disease has been reported infrequently. We present a patient of adult B lineage ALL who was on maintenance chemotherapy and developed CMV pneumonia. Patient was managed with intravenous ganciclovir and had successful outcome. However, three weeks later patient had a relapse of ALL and died shortly after high dose chemotherapy.