One of the major challenges modern nephrology should face is the identification of biomarkers that are associated with histopathological patterns or defined pathogenic mechanisms that might aid in the non-invasive diagnosis of the causes of nephrotic syndrome, or in establishing prognosis sub-groups based on each type of disease, thus predicting response to treatment and/or recurrence. Advancements in the understanding of the pathogenesis of the different diseases that cause nephrotic syndrome, along with the progressive development and standardisation of plasma and urine proteomics techniques, have facilitated the identification of a growing number of molecules that might be useful for these objectives. Currently, the available information for many of the possible candidates identified to date, above all those discovered using proteomics, are still very preliminary. In this review, we summarise the available evidence for the different molecules that have been best assessed using clinical studies.