Since heparanase activity is associated with a loss of glomerular HS and consequent proteinuria, the present study was undertaken to determine plasma and urine heparanase levels in renal transplant recipients and chronic kidney disease (CKD) patients and to assess whether alterations in heparanase levels correlate with proteinuria and kidney function.We report that urinary heparanase is markedly elevated in patients with CKD and following kidney transplantation. Here, HPSE is linked to chronic kidney disease.