Objective: A difference in temperature between the affected and normal extremity is one of the signs or symptoms of reflex sympathetic dystrophy (RSD). These temperature differences are scored anamnestically, by palpation, or by measurements. We investigated the relationship between objective and subjective differences in skin temperature between the hands. Subjects and design: Fifty-one patients with RSD of one upper extremity participated (mean age 55 years, range 18-80). In the first 16 we investigated the reliability of the visual analogue scale (VAS) for recording perceived differences in skin temperature. In the remaining 35 patients the relationship between the VAS and objective infrared radiometry of the hands was investigated. Setting: Outpatients clinics of two university hospitals. Results: The VAS was found to be reliable in terms of response stability. There was no significant correlation between the objective and subjective outcomes. Conclusions: There is lack of correspondence between objective and subjective temperature measurements, which may be due to a normal discrepancy between objective and percieved temperature, and/or to alterations in perception due to RSD.