Limited data are available on the incidence of complex regional pain syndrome type 1 (CRPS1) and on demographic and medical risk factors for the development of CRPS1. The objective of this study was to investigate the incidence of CRPS1 in patients with a fracture using 3 sets of diagnostic criteria and to evaluate the association between demographic/medical factors and the development of CRPS1 diagnosed with the Harden and Bruehl criteria. A prospective multicenter cohort study of 596 patients (ages 18 years and older) with a single fracture of the wrist, scaphoid, ankle, or metatarsal V, recruited patients from the emergency rooms of 3 Dutch hospitals. Of the 596 participants, 42 (7.0%) were diagnosed with CRPS1 according to the Harden and Bruehl criteria, 289 (48.5%) according to the International Association for the Study of Pain criteria, and 127 (21.3%) according to the criteria of Veldman. An analysis of the medical and demographic differences revealed that patients in whom CRPS1 later developed more often had intra-articular fractures, fracture dislocations, rheumatoid arthritis, or musculoskeletal comorbidities. An ankle fracture, dislocation, and an intra-articular fracture contributed significantly to the prediction of the development of CRPS1. No CRPS1 patients were symptom free at 12 months (T3). At baseline, patients with CRPS1 had significantly more pain than patients without CRPS1 (P<.001). The incidence of the diagnosis of CRPS1 after a single fracture depends to a large extent on the diagnostic criteria used. After a fracture, 7% of the patients developed CRPS1 and none of the patients were free of symptoms at 1-year follow-up. (C) 2012 International Association for the Study of Pain. Published by Elsevier B. V. All rights reserved.