Immunodeficiency states have been implicated in autoimmune diseases. Early recognition of these states is important because prophylaxis can prevent morbidity and mortality. The following is a case report of a 57-year-old male who presented with recurrent infections. He was found to have IgM deficiency. All of his infections were treated appropriately with successful responses. He developed glomerulonephritis, which was read by the pathologist as post-infectious glomerulonephritis. Despite antibiotic therapy, his renal function never recovered, leading to permanent hemodialysis. The patient's renal biopsy exhibited histological features compatible with a membrano-proliferative glomerulonephritis. Retrospectively, it is likely that this patient had autoimmune glomerulonephritis, explaining his failure to respond to antimicrobials.