Aim Initial heparin locks instilled after tunnelled dialysis catheter (TDC) insertion can leak causing systemic anticoagulation and also promote staphyloccocal biofilm formation, predisposing to catheter-related infection (CRI). The 1000 U/mL concentration is thus advocated as the optimal dose for preventing catheter bleeding and malfunction. The effect of lower heparin concentrations on further lowering these complications is not known. We compared early TDC outcomes between a non-standard ultra-low (500 U/mL) and standard initial heparin locks (1000 and 5000 U/mL). Methods This was a retrospective study on prospectively collected data on 238 de novo internal jugular TDCs placed by nephrologists. Cases were categorized into groups 1, 2 and 3, according to initial heparin lock: 500 [n = 30], 1000 [n = 180] and 5000 U/mL [n = 28] respectively. Bleeding and malfunction within 24 h of TDC insertion, 30 days CRI-free catheter survival and the effects of clinical and laboratory factors on bleeding were evaluated. Results Bleeding events were similar in groups 1, 2 and 3 (7 vs 14 vs 13 , respectively, P = 0.61). Malfunction was only seen in group 2 (3.3 ). Thirty-day CRI-free catheter survival was comparable (96 vs 98 vs 97 , respectively, P = 0.22), giving a cumulative CRI rate of 0.76/1000 catheter days. All CRIs were staphylococcal. Univariate analysis did not reveal any significant predictors of catheter bleeding. Conclusion Immediate TDC bleeding, malfunction and CRI rate are not influenced by heparin lock concentrations =5000 U/mL in this low-risk cohort. However this needs to be corroborated in higher risk patients.