Serum and urine soluble interleukin-2 receptor (SIL-2R) levels were determined with ELISA method in 36 cases of nephrotic syndrome in order to investigate the significance of the change of SIL-2R level. The results showed the values in nephrotic stage group (n = 22) exceeded those in nephrotic stage remission group (n = 14, P < 0.01) and those in healthy controls (n = 20, P < 0.01). However, there was no difference of SIL-2R values either in serum or urine between nephrotic stage remission group and healthy controls (P > 0.05). Serum SIL-2R values were correlated with those of serum creatinine (r = 0.44, P < 0.01) and urine SIL-2R values were correlated with those of urine protein excretion (r = 0.48, P < 0.01). The study suggests that increased concentration of SIL-2R can serve as an indicator of nephrotic syndrome activation and/or exacerbation of renal dysfunction.