Common clinical manifestations in patients with IgG subclass deficiency include recurrent respiratory tract infection, recurrent otitis media and sinopulmonary infection by virus or bacteria. The administration of intravenous immunoglobulin(IVIG) has been regarded as the most effective therapy in these patients. We experienced a 22-year-old patient with IgG3 subclass deficiency and recurrent fungal infection of oral cavity and lips. IVIG was given at 0.2g/㎏/dose twice a month for 6 months. After treatment with IVIG, the patient improved clinically.