We aimed to assess whether subcutaneous lignocaine affects the success rate of intravenous cannulation using a randomized clinical trial. Pre-prepared cannulation packs, 50% containing local anaesthetic, were used to cannulate consecutive consenting patients presenting to the Emergency Department who required cannulation as part of their routine treatment. Doctors with less than four years postgraduate experience randomly selected a pack to perform cannulation and completed a data collection form after each cannulation. Eighty-seven patients received lignocaine with 73 (83.9%) successfully cannulated on the first attempt, 79 patients were cannulated without lignocaine with 64 (81%) successfully cannulated on the first attempt. Subcutaneous lignocaine did not significantly affect the success rate of intravenous cannulation on the first attempt (P = 0.5). Subcutaneous lignocaine has been shown to significantly reduce the pain of intravenous cannulation. This study supports the use of local anaesthesia for all routine venous cannulation.