Breast conservation by wide local excision for early breast cancer is now considered safe and should be considered default therapy wherever possible. Unfortunately, this requires access to costly radiotherapy centers. Many women in the developing world or for that matter in wealthy countries with large land masses and small populations do not have access to radiotherapy and are therefore denied the option of breast-conserving surgery. Whole-breast radiation by external beam after tumorectomy is predicated on the belief that latent foci of subclinical cancer outside the index quadrant are responsible for local recurrence. We do not think this is the case, as over 90% of these recurrences occur in the index quadrant. In this paper we describe a novel system for intra-operative radiotherapy using a mobile unit that should, in theory, be able to replace 6 weeks of external beam from a linear accelerator. The technique, TARGIT, is currently undergoing a multinational clinical trial in comparison with conventional external beam. If we can prove at least equivalence in outcome, then breast-conserving surgery might become available to all women in the developing world and to those living long distances from the nearest radiotherapy center.