OBJECTIVE To evaluate the efficacy of peripheral intravenous (IV) cannula site joint immobilisation by splint application on functional duration of peripheral IV cannula in neonates. DESIGN Randomised controlled trial. SETTING Neonatal intensive care unit of a tertiary care hospital. PARTICIPANTS Neonates requiring continuous IV infusion for an expected duration of more than or equal to 72 hours. INTERVENTION Eligible cannulations were randomised to either "splint" or "no-splint" group. In the splint group, a cardboard splint was used to immobilise the joint at peripheral IV cannula site. No attempt was made to immobilise the limb in the no-splint group. OUTCOME MEASURE Functional duration of a peripheral IV cannula measured as interval from time of insertion to the development of predefined sign of removal (extravasation, blockage, inflammation). RESULTS A total of 69 peripheral IV cannulations in 54 neonates were randomised to either the splint (n = 33) or no-splint group (n = 36). Both groups were comparable in birth weight, gestation, site of cannulation and nature of fluids administered. Mean functional duration of cannula was lesser in the splint group compared to the no-splint group (h; 23.5 (SD15.9) vs 26.9 (SD15.5), mean difference: -3.3 h, 95% CI -11.02 to 4.3 h) although the difference was not statistically significant (p = 0.38). Extravasation at cannula site was found be the commonest indication for cannula removal in both the groups (84% vs 76.5%). CONCLUSION Joint immobilisation with splint at cannula site did not improve the functional duration of peripheral IV cannula.