A scoring system for the clinical severity of reflex sympathetic dystrophy (RSD) is proposed. The following signs and symptoms were considered to be significant: pain, reduction of finger flexion, swelling, temperature changes, discolouration, sensory disturbances, shoulder pain and loss of movement, increased sweating, and hair/nail growth changes. One point was assigned for strong expression of most of these features, half a point for moderate expression and no point if the feature was absent. A total score of 4 points was assumed, empirically, to indicate a mild degree of RSD, and the maximum score of 10 to indicate the most severe form of RSD. One hundred and forty-six patients with RSD of the hand were classified according to this system. Seventy-four patients (51%) had a score of 4-6, 51 patients (35%) a score of 6.5-8, and 21 patients (14%) a score of 8.5-10. Use of this system will allow more precise analysis of RSD patients and facilitate comparisons between studies.