Objective To study the relationship between urinary laminin(LN) and diabetic nephropathy.Methods Using the method for concentrating urinary laminin based on precipitation with PEG-4 000 and γ-globulin.The concentration of LN in the urine of 83 diabetics was measured by RIA.The concentration of micro-albumin and Ccr in the urine and the levels of plasma glucose and HbA1c were also measured.Results The choice of 150g/L of PEG-4 000 and 0.5 g/L of γ-globulin was the best method for concentrating urinary LN.The urinary LN in all groups was significantly higher than that in control group.Conclusion Urinary LN is an indicator in the diagnosis of the early diabetic nephropathy.