Hypocomplementemic urticarial vasculitis syndrome is an immune complex-mediated disease of unknown etiology. The clinical course is characterized by urticaria, conjunctivitis, joint pain, and hypocomplementemia. We here report a case of a child with hypocomplementemic urticarial vasculitis syndrome that progressed to nephritis. Renal biopsy was consistent with diffuse proliferative glomerulonephritis with diffuse subendothelial immune deposits. He responded well to a combination of steroid and mofetil micofenolate.