Membranous nephropathy (MN) is one of the most common causes of nephrotic syndrome in adults and can be seen in association with other diseases, including malignancy, drugs, infections, or autoimmune diseases. Over the last decade, great progress has been made in understanding the pathogenesis of the disease, resulting from the discovery of several target antigens by use of laser microdissection/mass spectrometry methodology. This technique has proven to be the most sensitive method available and has the advantage of testing for all the target antigens at one time.