Kimura's disease is a rare chronic inflammatory disease, which typically occurs in middle-aged Asian men. This benign lymphoproliferative disorder with tissue eosinophilia is clinically characterized by painless subcutaneous swelling or induration, affecting the head and neck region. Here we present a 42-year-old Japanese woman with a giant tumor on the right inguinal region. The tumor was diagnosed as Kimura's disease, because of massive infiltration of lymphoid follicle-forming lymphocytes and eosinophils with elevated serum immunoglobulin E and blood eosinophilia. She also had nephrotic syndrome histopathologically diagnosed as membranoproliferative glomerulonephritis (MPGN). Renal involvement is known as one of the associated conditions with Kimura's disease. The skin and renal diseases were successfully treated with corticosteroids and surgical removal of the mass.