The anxiety experienced by patients undergoing surgical procedures is well documented and may affect the outcome of any operation This has not been considered in modern urological surgery which is moving away from highly-invasive techniques towards minimal and even non-invasive procedures Little work has been earried out to examine the patient's reaction to this new technology This work has two aims to assess patient anxiety before and after different procedures for renal calculus removal and to identify, where possible, factors that contribute to pre- and post-operative anxiety The main method of quantifying stress was the measurement of palmar sweat by means of an evaporimeter Other measurements used were a bi-polar visual analogue scale and the Spielberger State Anxiety Questionnaire. The results of the study demonstrated a highly significant reduction in the palmar sweat production (P < 0.0001) and score obtained for the analogue scale (P < 0.05) following open surgery, but no changes before and after treatment in any of the variables in patients undergoing percutaneous nephrolithotomy or lithotripsy Analysis of the data in relation to the surgery demonstrated a significantly higher pre-operative analogue score in patients undergoing open surgery compared with lithoripsy (P < 0.05) Post-operatively, pahents undergoing hthotnpsy had a significantly higher palmar sweat response compared with patients undergoing open surgery (P < 0.01) Pre-operatively, fear of a general anaesthetic was identified as a factor contributing to anxiety and post-operahvely, pain was the most commonly identified stressor The implications of these results to the patient and to both nursing and medical staff in terms of practice are discussed This must include a careful pre-operative explanation