Background: The appropriate intensity of treatment for patients with advanced incurable cancer remains uncertain. Our study examines trends in population-based treatment following diagnosis for metastatic colon and rectal cancer in elderly adults. Methods: We used the Surveillance, Epidemiology, and End Results – Medicare database to identify persons aged 65 and older who were diagnosed with distant stage colon (N=12156) and rectal cancer (N=3071) between 2000 and 2007. We assessed treatment patterns over the year after diagnosis with a focus on chemotherapy and related services. For each year, we report the percent of patients receiving chemotherapy, hematopoietic growth factors, and antiemetics/premedication. For those patients who received chemotherapy, we estimated, by year, the median number of days from the first to the last chemotherapy claim. Results: From 2000 to 2007, the percent of patients receiving chemotherapy increased from 39.6% to 44.4% for colon patients and from 46.6% to 59.2% for rectal patients. The median duration of chemotherapy increased by more than 40 days. The type of chemotherapy used changed dramatically. Oxaliplatin and Bevacizumab were not available in 2000, but by 2007, a substantial portion of colon and rectal cancer patients received Oxaliplatin (28.4% and 37.6%) and Bevacizumab (24.4%. and 33.2%). The percent of patients receiving hematopoietic growth factors rose appreciably from 3.7% to 23.2% for colon patients and from 5.2% to 27.4% for rectal patients. From 2000-2007, use of antiemetics/premedication increased from 27.2% to 44.3% for colon patients and from 32.9% to 56.9% for rectal patients. Conclusions: The use and intensity of chemotherapy related treatment for CRC patients with advanced cancer has increased markedly from 2000 to 2007. Many of these therapies are very expensive. ASCO has encouraged realistic conversations about the potential benefits and limitations of disease-directed therapy with the hope of improving patients’ quality of life while reducing medical treatment costs. Our findings demonstrate the need for physicians to assess their treatment practices relative to health care costs and patient prognosis.