As a result of changes to surgical training in the United Kingdom, there has been a significant reduction in the number of hours worked by surgical trainees per week and in the total duration of surgical training. For trainees to achieve an acceptable level of surgical operative competence, the learning environment in the operating theatre needs to be optimized. In this context, an instrument to measure the learning environment in the operating theatre has been developed. Through a review of the literature and exploratory interviews with trainers and trainees, items that contribute to the learning environment in the operating theatre were identified. Based on these items a questionnaire was drawn up. For validation purposes, the questionnaire was circulated amongst basic surgical trainees on the Aberdeen rotation. This instrument was found to have high reliability and validity. Its potential usefulness for informing committees responsible for overseeing surgical training is discussed.