Kidney grafts begin normal function immediately after transplantation, after several, or after dozen or so days delay. Acute Kidney Insufficience (AKI), Nephrotic Syndrome (NS) and Chronic Allograft Nephropathy (CAN), sometimes defined as “Interstitial Fibrosis / Tubular Atrophy (IF/TA) without any specific etiology” (Reuter et al., 2010), are the main types of complications connected with kidney transplantation. In the diagnosis of the function of transplanted renal allografts, activities of enzymes excreted into urine by particular fragments of nephron are used. Increase of enzymuria precedes some clinical symptoms and is a more sensitive diagnostic marker than tubular proteinuria. Increase of enzymuria may also be useful for determination the time since renal tubules damage took place. Fructose-1,6 – bisphosphatase (FBP-1,6)the principal enzyme of gluconeogenesis and N-acetyl-β-hexosaminidase (HEX)the most active of the lysosomal exoglycosidases, taking part in the degradation of glycoconjugates (glycoproteins, glycolipids, proteoglycans), are markers used for monitoring kidney allograft function both in early and late post transplant periods, because of localization in the proximal contorted and straight tubules of nephron.