Glomerulomegaly is a histologic finding present in idiopathic pulmonary hypertension, congenital cyanotic heart disease, morbid obesity associated with sleep apnea syndrome, sickle cell disease, and polycythemic states. This study examines the case of a 34-yr-old woman with idiopathic pulmonary artery hypertension who presented with nephrotic-range proteinuria. Kidney biopsy revealed enlarged glomeruli with mesangial-proliferative glomerulonephritis. A review of the pertinent literature and a discussion of the proposed pathophysiologic mechanisms leading to glomerulomegaly are presented.