In order to develop a suitable secondary renal disease model and diagnostic markers of renal disease in the rat, the change of PIIIP (aminoterminal procollagen III peptide) in serum and hydroxyproline levels in the renal tissue that reflect the synthesis of extracellular matrix (ECM) during development of experimental renal diseases were observed. Two types of experimental primary diseases, diabetes mellitus administrated by streptozotocin (STZ, 75 mg/kg, i.p.) and liver cirrhosis produced by bile duct ligation/scission (BDL/s) operation, were induced. The hydroxyproline level increased according to the high PIIIP and NCl(carboxyterminal procollagen IV peptide) in Western blot analysis as early as 1 week in the STZ treated-rat kidney. Increased renal ECM was observed at 15 weeks in STZ and BDL/s model under the microscopic examination. High PAS positive reaction was found in capillary basement membrane in STZ treated-rats and mesangium in BDL/s operated rats at this time, showing the histological characteristics of diabetic nephropathy and cirrhotic glomerulonephritis in human, respectively. Such secondary renal failure were supported by additional tests including urinalysis and renal function test. The serum PIIIP detected by ELISA was a useful parameter to estimate synthesis rate of renal ECM during development of renal disease without extrarenal fibrosis i.e. liver cirrhosis in rats. This study is proposed that STZ treatment or BDL/s operation may be a suitable experimental animal model for the induction and development of chronic secondary renal diseases. Morover, it was found that hydroxyproline level in renal tissues was a good parameter of the change of renal ECM at the early stage of the diseases without apparent histological changes. Especially, serum PIIIP could be a choice as a diagnostic or prognostic marker during the development of renal diseases in rats.