An 84-year-old patient underwent anterior resection for rectal cancer (RS, T4a, N2, M0, Stage Ⅲb), without adjuvant chemotherapy. Liver metastasis 30 mm in diameter was found in the S7/8 segment 2 years and 6 months after surgery, and segmentectomy of the liver was performed. One year after hepatectomy, lung metastasis 9 mm in diameter was detected in the right S1 lobe. The tumor enlarged after a 2-month follow-up period. We decided to apply stereotactic radiotherapy (50 Gy/10 Fr) to control the lesion. The tumor shrunk and became a scar after treatment. The patient was in good health without any recurrences 7 months after stereotactic radiotherapy. Surgical resection is an optimal method to control lung metastasis from colon cancer when operable; however, there are cases with no indication for surgery due to co-morbidities. Stereotactic radiotherapy can be an effective treatment for lung metastasis from colon cancer when surgery is contraindicated.