This randomized controlled study on 86 patients compared the level of pain experienced by patients on instillation of local anaesthetic into the palm with a 23-gauge and a 27-gauge (dental) needle in open carpal tunnel decompression. Patients were asked to score the amount of pain they experienced during the injection of the local anaesthetic and their level of anxiety about future injections using a visual analogue scale (VAS) and a four-point verbal response scale (VRS). The mean pain and anxiety scores on the VAS were significantly lower in the dental needle group. There was significant correlation between the pain and anxiety VAS scores. When infiltrating local anaesthetic into the palm for open carpal tunnel decompression, the use of a fine (dental) needle can reduce the pain on that occasion and the anxiety concerning future injections likely to be experienced by the patient.