Focal Segmental Glomerulosclerosis (FSGS) is a characteristic histopathological lesion that is indicative of underlying glomerular dysfunction. It is not a single disease entity but rather a heterogeneous disorder that is an important cause of nephrotic syndrome and kidney failure in children and adults. The aim of this Kidney Health Initiative project was to evaluate potential endpoints for clinical trials in FSGS. This paper focuses on the data supporting proteinuria as a surrogate endpoint. Available data support the use of complete remission of proteinuria in patients with heavy proteinuria as a surrogate endpoint for progression to kidney failure.