Measurement of soluble CD30 (sCD30) levels may predict acute rejection episodes (ARE). To explore the value of sCD30 after transplantation, we tested serum sCD30 levels in 58 kidney transplant cases at 1 day before and 7 and 28 days after transplantation by enzyme-linked immunosorbent assay (ELISA). The incidences of ARE after kidney transplantation were recorded simultaneously. Meanwhile, 31 healthy individuals were selected as a control group. The results showed a relationship between sCD30 level in serum before kidney transplantation and the incidence of ARE. However, the relationship was more significant between serum sCD30 levels at day 7 after kidney transplantation and the incidence of ARE. There was no obvious relationship between serum sCD30 levels at day 28 after kidney transplantation and the incidence of ARE. These results suggested that the level of sCD30 at day 7 posttransplantation provides valuable data to predict ARE.