Membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults. At early stage of MN, minimal change disease (MCD) is a main differential and diagnosis here relies on electron microscopy (EM). It would be useful to have a specific and sensitive method that can be used on paraffin embedded sections for differentiating early MN from MCD, especially in places where EM is not available. Paraffin embedded sections from 47 cases have been stained with C4d monoclonal antibody. The cases included 16 cases of idiopathic MN, 23 cases of MCD and 8 borderline cases. The later were MCD cases with prominent GBM, so early MN can't be excluded. All cases of MN cases showed positive results with C4d antibody, 22 out of 23 cases of MCD showed negative results with the C4d antibody. The only MCD case with positive result was proved one year later to be Systemic Lupus Erythematosus. Two borderline cases stained positive for C4d antibody, one of them proved to be MN on follow up and the other one lacked follow up data. So, it was concluded that C4d antibody is a specific and sensitive method of differentiating early MN from MCD. Monoclonal C4d antibody has comparable results to polyclonal C4d antibody that was used on paraffin embedded sections in other studies.