Pre op er a tive ra dio ther apy ± che mo ther apy became the stan dard treat ment for lo cally ad vanced rec tal can cer. De spite better lo cal con trol with this ap proach, there was not seen a sig nif i cant improve ment in over all sur vival and dis ease free sur vival, yet. The main dis ad van tage is tox ic ity that can be de vel oped, es pe cially con com i tantly with che mo ther apy. Tox ic ity can be acute and late. Acute com pli ca tions are tran si tory, but late might lead to per ma nent dam age and con se quently are more sig nif i cant for pa tients. To day, there are tech ni cal op por tu ni ties in re duc tion of acute and late ra di a tion tox ic ity in the treat ment of rec tal can cer. With the im ple men ta tion of 3D conformal ra dio therapy (3D CRT) and in ten sity mod u lated ra di a tion therapy (IMRT) tech niques in clin i cal prac tice sig nif i cant ac cu racy, better dose dis tri bu tion and safety in the treat ment of rec tal can cer pa tients is achieved, with max i mal spar ing of sur round ing nor mal tis sue. Uti liza tion of ad vanced tech niques and new soft ware so lutions can keep ad verse ef fects on sat is fac tory lev els with ex cel lent lo cal con trol. Keywords: rec tal can cer, pre op er a tive ra dio ther apy, tox ic ity, ra dio ther apy tech niques.