BACKGROUND: Reported data regarding chronic kidney disease (CKD) in haematopoietic stem cells transplantation (HSCT) recipients are highly discrepant. Materials and methods. We undertook a retrospective single-centre study in order to assess the rate, risk factors and outcome of HSCT-associated CKD in 123 allogeneic HSCT patients. RESULTS: Twenty-four months after HSCT, CKD [e.g. glomerular filtration rate (GFR) estimated using the MDRD formula <60 ml/min/1.73 m(2)] was noted in 49 patients (40%). Age >or= 45 years, early acute kidney injury and a baseline GFR < 90 ml/min/1.73 m(2) predicted the occurrence of CKD at 24 months after HSCT. One hundred and six patients (45 with and 61 without CKD at 24 months) were followed up for more than 36 months (range 36-142). Among the 45 patients with CKD at 24 months after HSCT, CKD persisted in 30 (67%), 10 patients (22%) showed a transient improvement in GFR but retained CKD and 10 patients (22%) had a sustained improvement of GFR. Among 61 patients without CKD at 24 months after HSCT, 3 (5%) developed CKD during the follow-up. Our data indicate that HSCT-related CKD probably includes two subsets: a frequent early-onset CKD, a consequence of ARF in older patients with pre-existent renal impairment, and a rare late-onset CKD occurring more than 2 years following HSCT. CONCLUSIONS: Careful monitoring of renal function is mandatory in patients undergoing HSCT, especially old patients with pre-existent renal impairment.