Thirty-three patients with unilateral Colles fracture were evaluated by clinical and electrodiagnostic methods to determine the frequency of concomitant ipsilateral carpal tunnel syndrome. Four cases were documented, an incidence of 12.1%; this is two to four times greater than the incidence previously reported in the orthopaedic literature. Four other cases showed bilateral carpal tunnel syndrome, on of which was more more severe on the fracture side. Although electrodiagnosis was not found to be a more sensitive diagnostic indicator than was careful history and physical examination is these patients, it was useful in objectively confirming the clinical impression and assessing the severity of involvement. Recovery of hand function was not adversely affected by the presence of carpal tunnel syndrome in our cases. In view of the rather frequent occurrence of this complication, it is recommended that all patients with Colles fracture be carefully evaluated for the presence of symptoms or signs suggesting median nerve compression, and that all suspected cases by referred for early electrodiagnostic evaluation.