Background: The chemokine RANTES is a potent chemoattractant for T cells and monocytes that has been shown to enhance inflammation. The aim of our study was to investigate whether RANTES is upregulated within the early post-transplantation period that may influence short-time allograft function rate. Methods: Serum and urine samples from transplanted renal allograft recipients (n = 17) were obtained from specimens taken for diagnostic reasons. Four patients developed biopsy-proven rejection episodes within the first month. Time course of RANTES was studied within the first 12 days after renal transplantation using ELISA technique. Data were tested for significances between patients with rejection and without rejection, compared to healthy volunteers as controls, and correlated with clinical data. Results: In the control group RANTES concentration was 37.2 ± 2.7 ng/ml (serum) and 8.1 ± 1.3 pg/ml (urine), respectively. In transplanted recipients serum RANTES was significantly upregulated up to 132 ± 28 ng/ml on day 1 after transplantation and remained elevated within the first 12 days (n = 17). Time course of urine RANTES demonstrated elevated concentrations with 754 ± 115 pg/ml on day 1 followed by an continuous decrease to 22.3 ± 7 pg/ml on day 12 (n = 17). No significant differences could be detected between patients with rejection and without rejection episodes. Conclusions: In contrast to data of other urinary marker molecules (like IL-6), there are no significant differences between the rejection and non-rejection group. RANTES is therefore not suitable for early detection of rejection. Nevertheless, serum and urine RANTES concentrations were highly elevated in freshly transplanted renal allograft recipients reflecting an activated immune system.