The risk for serious complications associated with modern radiotherapy is relatively low. Compared with conventional radiotherapy, 3DCRT and IMRT allow higher doses to be given more safely. The use of IMRT increases the time and effort required by physicians and physicists. Although there is a clear move toward IMRT, 3DCRT is considered standard. The quality assurance procedures for and fundamental questions regarding IMRT are evolving, including the radiobiologic consequences of altered time-dose fractionation and the greater dose heterogeneity in the target. Defining an accurate target volume and routinely correcting for set-up error and organ movement before each treatment promise to reduce the complications associated with EBRT in the next 5 years. Complications following prostate brachytherapy are better understood now than 10 years ago. Dosimetric or patient selection factors that correlate with a higher risk for complications, such as acute retention, strictures, severe prolonged urinary symptoms, fistulas, proctitis, and impotence, often can be accounted for or avoided. Finally, the role of radiation protectors is beginning to be addressed. It is hoped that these advances will eliminate toxicity associated with radiotherapy and increase cure rates.