The aim of this study was to investigate endoscopically and histologically rectal mucosa complications in bilharzia patients. Coprology using KATO's technique was carried out in 1406 school children aged 4 to 18 years. 134 (9.53%) were infested. Among the infested school children and the sample population, a random selection of 80 school children (40 infested and 40 of sample population) was made, in whom rectoscopy and biopsy of rectal mucosa were carried out. The lesions found were classified on endoscopic and histologic basis. The prevalence of the disease 9.53% appears to be in constant regression. Inflammatory lesions are more common in bilharzia patients. Histology facilitated the unveiling of a specific rectitis in 72.5% bilharzia patients and 12.5% of the sample population. This study confirm the effectiveness of the several bilharzia eradication campaigns carried out in the Nkolbisson area. Rectoscopy with biopsy of the rectal mucosa should be reserved to symptomatic patients, in whom many coprologies have turned out negative.