OBJECTIVES: To examine the clinical characteristics and treatment patterns of colorectal cancer patients in the U.S. veteran population. METHODS:   A study sample from the Veterans Health Administration (VHA) Medical SAS datasets from October 1, 2005 through May 31, 2012 was analyzed. All patients diagnosed with colorectal cancer throughout the study period were identified using International Classification of Disease 9thRevision Clinical Modification (ICD-9-CM) diagnosis codes 153.xx and 154.xx.  Descriptive statistical analyses were performed using SAS v9.3 software. RESULTS:   There were 62,200 diagnosed colorectal cancer patients in the VHA population during the study period. Major comorbidities for these colorectal cancer patients were hypertension (n=18,309, 29.44%) and diabetes (n=10,891, 17.51%). Other minor comorbidities included hyperlipidemia and benign neoplasm of the colon. Common treatments prescribed for colorectal cancer patients were simvastatin and omeprazole.  Outpatient services were utilized by 99.71% of colorectal cancer patients, followed by pharmacy (91.94%) and inpatient visits (31.15%).  Costs for outpatient ($10,637, standard deviation [SD]=$17,125), pharmacy ($2,704, SD=$9,773), and inpatient services ($16,032, SD=$53,078) contributed to follow-up health care expenditures. Out of all colorectal cancer patients, 7,596 (12.21%) had Occult Blood (Fecal) Test results, with an average test result of 96.37. CONCLUSIONS:   Colorectal cancer treatment is complicated by the presence of both major and minor comorbidities. Further analysis in the context of complicated comorbid conditions is required to improve the overall burden of illness of colorectal cancer patients.