Double contrast enema and endoscopy are very important in the diagnosis of adenomas and early cancer of the colon and rectum. These exams can not only detect the presence, but also suggest the histologic diagnosis, of polypoid lesions of the colon. An Olivetti M24 Personal Computer was used to create a software to study the results obtained by double contrast enema, and to compare them with endoscopy and pathology. The data base is formed by 7 files: one anagraphic, 3 collecting the characteristics of the diagnosis--namely the radiologic, the endoscopic and the pathologic one-- and 3 multiple files featuring each lesion, as defined by the three diagnostic techniques. The software allows to evaluate the different lesions that can be detected by the three techniques in the same patient and to compare the diagnosis of presence to the morphologic features of each lesion. False negatives and false positives of each technique are easily recognized. It is also possible to characterize the single morphologic feature leading the radiologist and/or the endoscopist to express an opinion about the histologic diagnosis of each lesion and to compare them with pathological features. The first experience in clinical use of the software, in the analysis of the characters of 336 lesions in 218 patients, is described