PURPOSE: To determine the appearance of reflex sympathetic dystrophy (RSD) at magnetic resonance (MR) imaging. MATERIALS AND METHODS: Fifty-one patients with suspected RSD were prospectively evaluated at MR imaging with T1- and T2-weighted sequences and T1-weighted sequences with fat suppression before and after the intravenous administration of contrast material. RESULTS: RSD was confirmed in 45 patients. in 35 patients with stage 1 RSD, skin thickening (31 patients), tissue enhancement with contrast material (31 patients), and soft-tissue edema (six patients) were demonstrated. In five patients with stage 2 RSD, skin thickening (two patients), skin thinning (two patients), and infrequent contrast material enhancement (one patient) were demonstrated. There was no edema in this group of patients. In five patients with stage 3 RSD, inconsistent skin changes were also demonstrated; however, muscle atrophy (four patients) was demonstrated in this stage only. CONCLUSION: MR imaging was beneficial in the demonstration of soft-tissue abnormalities in patients with RSD. MR imaging may also help stage RSD, particularly stages 1 and 3.