The immunological functions of Ganoderma lucidum antlered form (AF) (Rokkaku-Reishi in Japanese), a variant type of Ganoderma lucidum, were investigated in C57BL/6 mice treated with cyclophosphamide (CY). Ganoderma lucidum AF alleviated CY-induced decrease in body weight and abnormal increase in blood neutrophil level, when the mice were fed a diet containing 2.5% Ganoderma lucidum AF starting one week before CY treatment (150 mg/kg, ip). The recovery of CD8+ and NK1.1+ cells in the spleen was accelerated in Ganoderma lucidum AF group compared to the control group. Ganoderma lucidum AF also both alleviated CY-induced splenic lymphopenia and suppressed the abnormal increase in splenocytes 7 days after CY treatment. These results suggest that ingestion of Ganoderma lucidum AF is beneficial for improvement of quality of life reduced by anti-cancer chemotherapeutic drugs such as CY.