An unusual case of nephrotic syndrome secondary to preeclamptic nephropathy is documented. The preeclampsia was associated with a transitional mole with coexistent fetus. A review of the literature revealed only one similar case reported previously. Immuno-pathologic examination of the renal biopsy revealed abundant IgM and fibrinogen within the glomeruli; electron microscopy showed numerous subendothelial and occasional intramesangial deposits of electron-dense material. The significance of these findings with regard to the pathogenesis of preeclamptic nephropathy is briefly discussed.