Patients and their physicians were asked to estimate the pain from needle aspiration and/or injection of joints or soft tissue using the visual analogue scale. On a 10-point scale, the mean score for patients prior to and after the procedure was 4.76 +/- 2.97 and 4.01 +/- 3.51, respectively, and for physicians was 4.15 +/- 2.45 and 3.36 +/- 2.08. Analysis of correlations revealed that prior to the procedure patients could predict their 'true' pain (after the procedure assessment) better (r = 0.765) than physicians could predict patients' pain (r = 0.542). However, physicians significantly improved their estimates of patients' scores by observing the procedure. After the procedure correlation between physician and patient scores increased to 0.62 (P = 0.003). The overall pattern of results suggests that experienced patients may be somewhat better than their physicians in predicting the level of pain they experience with a procedure, but that physicians' estimates appear to be accurate enough to allow them to give useful information about the degree of discomfort that a patient will experience during an invasive procedure.