 Preoperative chemoradiation leads to increased pelvic control and overall survival, but both distant and local disease control remain problematic in locally advanced rectal cancer patients. Enhancing the effect of chemotherapy and radiotherapy can increase tumor response as well as distant disease control. Patients who have complete response to therapy have increased sphincter preservation, and can possibly have more limited surgery full thickness local excision. When combined with standard chemotherapy, bevacizumab RHUMAB VEGF, Avastin has been shown to improve response and median survival in patients with metastatic colorectal cancer in a recent randomized trial, has led to increased activity in preclinical studies with radiotherapy, and has been found to be very well tolerated with chemoradiation in a phase I trial conducted at the M.D. Anderson Cancer Center MDACC in patients with locally advanced pancreatic cancer. The hypothesis is that the addition of bevacizumab to standard chemoradiation will safely lead to increased tumor response in patients with locally advanced rectal cancer. 