Recently, a combination of local irradiation and chemotherapy has been suggested as a standardized treatment for localized lymphoma. However, it has been difficult to establish a standard treatment for localized primary breast lymphoma simply because of its rarity. We report two cases of primary breast lymphoma successfully treated with a combination therapy including local radiation therapy. A 46-year-old woman with stage I primary breast lymphoma was irradiated with 30 Gy to the involved breast by 4 MV X-rays and 9 Gy to the involved field by electron beam after tumorectomy. Then three cycles of CHOP therapy were performed. She has been well and has shown no evidence of disease for 58 months. A 72-year-old woman with stage II primary breast lymphoma was treated with three cycles of CHOP therapy followed by irradiation with 40 Gy per breast by 4 MV X-rays. She is well and has been disease-free for 49 months. We suggest that a combination of local irradiation and short course of chemotherapy can be useful in the treatment of primary breast lymphoma.