Uracil and tegafur (in a molar ratio of 4:1 [UFT]) plus calcium folinate comprise the components of the oral agent, Orzel, which appears to have activity comparable to intravenously administered 5-fluorouracil. This article describes the design of an open-label, disease-oriented, phase I trial of UFT plus calcium folinate in combination with simultaneous pelvic radiation for recurrent rectal cancer. This trial is designed to determine the maximum tolerated dose and dose-limiting toxicity of this regimen.