Human nephrotic syndrome has been related to mutations in glomerular proteins. Mutations in the NPHS2 gene that encodes podocin have been described as responsible for steroid-resistant nephrotic syndrome. It has been advised to test for NPHS2 mutations in parallel or before giving steroid treatment in nephrotic syndrome patients in order to avoid unnecessary therapy. We identified NPHS2 mutations in Mexican children with nephrotic syndrome. The study included 13 children with nephrotic syndrome and 2 healthy control individuals; 8 patients were steroid-resistant and 5 were steroid-sensitive. We analyzed the 3rd exon of NPHS2 by DNA sequencing. Podocin heterozygous missense mutations L139R and L142P were found; the former was found in both steroid-sensitive and steroid-resistant children, while the latter was found in a steroid-resistant child. We conclude that NPHS2 mutations should be investigated to help decide the course of treatment in nephrotic syndrome patients.