Carpal canal size was examined as a risk factor associated with carpal tunnel syndrome in the workplace. Seven of 14 electricians had symptomatic carpal tunnel syndrome. On measuring cross-sectional areas by CT, affected workers had a cross-sectional area of 1.75 ± 0.21 cm2; control values were 2.53 ± 0.15 cm2 (p < 0.05). Individuals with a subclinical syndrome had an area of 1.83 ± 0.22 cm2, similar to the symptomatic group. Wrist circumference was not a predictor of smallest carpal canal area. Unusual bony and soft tissue structures within the carpal canal were easily identified with CT.