The authors discuss the general and radiologic characteristics of leiomyomas and leiomyosarcomas, based on experience with forty-five cases involving the digestive tract and a review of over one thousand cases reported in the literature. Thirty-six leiomyomas (oesophagus 9, stomach 18, small intestine 9) and nine leiomyosarcomas (oesophagus 2, stomach 2, small intestine 4, colon 1) were observed and compared with reports from the literature. Leiomyomas of the oesophagus lend themselves to radiologic surveillance since there is no tendency for lesion degeneration in this location. Leiomyomas of the stomach are frequently asymptomatic and discovered following radiologic or endoscopic examination. With involvement of the small intestine, the most sensitive radiologic examination remains angiography, even though the information provided does not allow evaluation of the evolution of the tumour. Localization in the colon remains rare.