Developments in technology and digital techniques in radiotherapy made 3-D conformal radiotherapy possible in the clinic. 3-D conformal radiotherapy enable to increase the therapeutic ratio by limiting the dose to the normal tissues while escalating the dose to the tumor volume (target). Clinical results proved that 10% to 20% dose escalation to the target does not increase the risk of complications. Conformal radiotherapy significantly improves the treatment results of the prostate cancer. Some promising results from preliminary trials in the lung cancer are also discussed. Introduction of 3-D radiotherapy is expensive and rises the standards and skills of the radiotherapeutic team.