Accelerated partial breast irradiation (APBI) is a novel method of post-operative radiotherapy that consists of irradiation of a limited volume of mammary gland immediately surrounding the tumour bed over a shorter time than whole breast irradiation. Several modalities are currently being explored as a means to deliver APBI, including multicatheter interstitial brachytherapy, the MammoSite breast brachytherapy catheter (Cytyc Corporation, Marlborough, MA), intraoperative radiation therapy and 3D conformal external-beam radiation therapy. To date, although still limited, randomised evidence is encouraging about the future role of APBI since it does not seem to jeopardise overall survival in patients with early breast cancer. Additional phase III studies are under way to determine the subgroups of patients who will really benefit from APBI.