Taurolidine-citrate(-heparin) lock solutions (TCHL) are suggested as a promising and safe method for the prevention of central line-associated bloodstream infections (CLABSI). To investigate the efficacy TCHL for the prevention of CrLABSI in paediatric oncology patients. An assessor blinded randomized controlled trial at the Princess Máxima Centre for paediatric oncology, the Netherlands, was performed from 2020-2023. Paediatric oncology patients receiving a tunnelled central venous access device (CVAD) were eligible. A total of 462 patients was required to compare the TCHL to the heparin-only lock (HL). Patients were followed-up for the first 90 days after CVAD insertion. The primary outcome was the incidence of the first CLABSI from CVAD insertion until the end of follow-up. Intention-to-treat and per-protocol analyses were performed. In total, 232 were randomized in the HL and 231 in the TCHL-group. A total of 47 CLABSIs were observed. The intention-to-treat analysis showed that a CLABSI was observed in 26 (11.2%) of the HL-group patients versus 21 (9.1%) of the TCHL-group patients; incidence rate ratio (IRR) of 0.81 (CI95%0.46-1.45), in favour of the TCHL-group. The per-protocol analysis showed that a CLABSI was observed in 10 (7.9%) of the HL-group patients versus 6 (4.8%) of the TCHL-group patients; IRR of 0.59 (CI95%0.21-1.62) in favour of the TCHL-group. Adverse events were more common in the TCHL-group but rarely reported. No difference was detected between the TCHL and HL in the incidence of CLABSI in paediatric oncology patients. ClinicalTrials.gov NCT05740150.