&NA;To evaluate whether there is a relationship between the viscoelastic properties of the rectum and its surface, barium enema and rectal accommodation studies were performed under standard conditions in 46 subjects (25 adults, 21 children) with chronic idiopathic constipation. In adults, a significant correlation was found between rectal surface at barium enema and the minimum radius of rectal distention with a balloon necessary to higher wall tension changes (r=0.68;P<0.01). In both adults (r=0.48;P<0.05) and children (r=0.57;P<0.01), negative correlations were found between the surface of the rectum and its elasticity. It is concluded that rectal accommodation studies produce data comparable to those of radiologic examinations and may therefore be used repetitively, and without fear of radiation, as follow‐up studies on constipated patients.