Hypofractioned radiation therapy regiments are increasing being used to treat patients desiring breast conserving therapy.Shortened treatment regiments have been shown to improve quality of life and increase the compliance of adjuvant radiation therapy.Meanwhile, early data suggests that such regimens produce similar disease control and cosmetic outcome to traditional protracted radiation treatments, at significantly less cost.Mature data, accumulating in the prospective randomized setting of whole breast accelerated radiation, is encouraging.However, only one prospective randomized trial has been reporting demonstrating the equivalence of accelerated partial breast irradiation (ABPI) to traditionally fractioned whole breast irradiation (WBI).Unfortunately, the trial utilized one of the least commonly employed methods of APBI, namely interstitial brachytherapy.Numerous prospective trials are enrolling patients utilizing more commonly employed means of delivery of ABBI, namely external beam radiation therapy and balloon or strut based intra-cavitary devises.Until mature data is available from these trials, various organizations such as the American Society for Radiation Oncology (ASTRO), have developed consensus guidelines to help determine appropriate patients for APBI.The purpose of the discussion is to present several case studies, in early stage breast cancer, to illustrate the utility of various treatment guidelines in selected appropriate candidates for accelerated breast irradiation.Lastly, we will discuss the developing literature that suggests that the guidelines, discussed above, do not necessarily correlate with actual patient outcomes when treated with various forms of accelerated breast irradiation.Ultimately, physician comfort and experience along with prudent patient selection may be the guiding light in the application of increasingly adopted techniques, for which little long term data exists to aid in decision making.