Temporal changes in short-term mortality following surgery for colorectal cancer (CRC) are unknown. We examined temporal changes in 30- day postoperative mortality, as well as changes in preoperative and postoperative disorders that could contribute to 30- day mortality. Using national Veterans Administration (VA) administrative data, we identified patients with CRC during 1987- 2000 who received surgical resection. Cox proportional hazards models were used to evaluate the association between the risk of 30- day mortality and year of surgical resection, while adjusting for several preoperative disorders, disease comorbidity, as well as hospital surgical volume. A total of 32,621 patients were identified. The 30- day postoperative mortality declined from 4.7% during 1987- 1988 to 3.9% during 1998- 2000. Patients who received surgical resection during 1992- 1994, 1995- 1997, and 1998- 2000 had a 14, 14, and 27% lower adjusted risk of 30- day mortality, respectively, compared with those resected in 1987- 1988. Preoperative disorders associated with increased mortality included chronic pulmonary disease, congestive heart failure, diabetes, hemiplegia/paraplegia,moderate/severe liver disease, and renal disease. Significant declines were observed in several postoperative disorders including anesthesia complications and thromboembolism. An improvement in 30- day postoperative mortality following surgical resection for CRC was observed. Declining preoperative and postoperative disorders, as well as improvements in surgical care, could partly explain these findings. Temporal changes in short-term mortality following surgery for colorectal cancer (CRC) are unknown. We examined temporal changes in 30- day postoperative mortality, as well as changes in preoperative and postoperative disorders that could contribute to 30- day mortality. Using national Veterans Administration (VA) administrative data, we identified patients with CRC during 1987-2000 who received surgical resection. Cox proportional hazards models were used to evaluate the association between the risk of 30- day mortality and year of surgical resection, while adjusting for several preoperative disorders, disease comorbidity, as well as hospital surgical volume. A total of 32,621 patients were identified. The 30- day postoperative mortality declined from 4.7% during 1987- 1988 to 3.9% during 1998- 2000. Patients who received surgical resection during 1992- 1994, 1995-1997, and 1998-2000 had a 14, 14, and 27% lower adjusted risk of 30- day mortality, respectively, compared with those r elicited in 1987- 1988. Preoperative disorders associated with increased mortality included chronic pulmonary disease, congestive heart failure, diabetes, hemiplegia / paraplegia, moderate / severe liver disease, and renal disease. Significant declines were observed in several postoperative disorders including anesthesia complications and thromboembolism . An improvement in 30- day postoperative mortality following surgical resection for CRC was observed. Declining preoperative and postoperative disorders, as well as improvements in surgical care, could yet explain these findings.