Abstract: Radiotherapy after breast-conserving surgery increases local control. We tested the feasibility of limited surgery with tumor bed irradiation only with 192Ir in a selected group of patients with stage I breast cancer. Twenty-five breasts in 24 women more than 60 years old with low- or intermediate-grade stage I tumors were treated with placement of interstitial catheters at the time of lumpectomy and axillary node dissection. This procedure was followed by after-loading with low-dose 192Ir to deliver 20–25 Gy to the tumor bed over 24–48 hours. There were neither local recurrences in the breast nor distant recurrences at a median follow-up of 47 months (range 25–90 months). Cosmetic appearance ranged from very good to excellent. There were no long-term complications. It is feasible to treat a select group of patients with tumor bed irradiation, using relatively low doses of interstitial irradiation, with excellent local control and no significant morbidity.