We present a case of membranous nephropathy (MN) associated with esophageal squamous cell carcinoma (ESCC) with a high serum level of squamous cell carcinoma antigen (SCC). ESCC reached complete response (CR) for radiotherapy, with a partial remission of the proteinuria and decreased serum SCC levels. Six months after radiotherapy, the ESCC recurred, and the patient was treated with endoscopic mucosal resection (EMR), achieving a pathologic CR and disappearance of proteinuria and normalized serum SCC levels. The correlation of proteinuria and the serum level of SCC indicates that SCC could be a pathogenic antigen, responsible for the pathogenesis of MN in this patient.