The aim of this study was to determine whether there is a relationship between sedentary occupation and the occurrence of rectal and sigmoid cancer. 105 patients with histologically proven rectal cancer were questioned. 55 patients with gastric carcinoma and 99 patients with cholelithiasis served as control groups. The percentage of patients with a sedentary occupation is significantly higher in the group with rectal cancer. In addition, the mean duration of the sedentary occupation is also longer. A direct relationship between the sedentary occupation and the tumor stage is obvious. It is concluded that a sedentary occupation-which leads to changes in the motility of the large bowel-had to be considered a risk factor in the occurence of rectal and sigmoid cancer.