Immunoglobulin M nephropathy (IgMN) is a primary glomerulonephritis which is characterized by variable degrees of morphological features ranging from minimal glomerular involvement to segmental or global sclerosis. No specific treatment is known to date for this disease because of uncertainties in etiopathogenesis. The mainstay treatment for this disease has been corticosteroids, which has varying degrees of resistance ranging from 0% to 50%. We present the case of a 59-year-old Caucasian male who was referred to the outpatient nephrology clinic for the evaluation of proteinuria and was diagnosed with IgMN. We successfully treated the patient with rituximab with resolution of his proteinuria.