A 27-year-old man receiving continuous ambulatory peritoneal dialysis (CAPD) developed high-grade fever, dyspnea, and hemoperitoneum 32 months after the start of CAPD. A chest computed tomograph showed fine reticular shadows in the bilateral lower lung fields. Cytomegalovirus (CMV) antigenemia were detected, and immunoglobulin (Ig) M and IgG antibodies for CMV were also positive. The absolute counts of helper T cells (478/microL) and the ratio of helper T cells/suppressor T cells (0.25) decreased, despite no evidence of hematologic or immunologic diseases, including human immunodeficiency virus (HIV) or human T cell lymphoma virus-1 (HTLV-1) infection, or the use of immunosuppressive drugs. All symptoms, including hemoperitoneum and the ratio of helper T cells/suppressor T cells, improved gradually and spontaneously. Acute and primary cytomegalovirus (CMV) infection induced hemoperitoneum in a patient who was receiving CAPD.