Abstract: Background: Colorectal cancer (CRC) diagnoses are frequently made through emergency presentations (EPs), a new cancer diagnosis following an emergency care episode or unplanned inpatient admission. The extent and implications of EPs are not well known in the Veterans Affairs (VA) health system, where robust CRC screening protocols exist. The impact of the COVID-19 pandemic on the route of CRC diagnosis also remains unclear. Methods: We conducted a retrospective cohort study of all incident CRC cases diagnosed nationally in the VA health care system from 2017 to 2021. We applied a previously validated algorithm to identify CRC EPs and used multivariable logistic regression and Cox proportional hazards models to examine the associations between EPs and CRC stage, treatment, and mortality. Results: We identified 9,096 patients with CRC, 28.1% of whom had EPs, with the proportion of EPs increasing over the study period from 26.4% in 2017-2019 to 31.4% in 2020-2021. Patients with EPs were more likely to have advanced stage disease (adjusted OR 1.70; 95% CI 1.53-1.88) and less likely to receive cancer treatment (adjusted OR 0.65; 95% CI 0.56-0.75) than patients without EPs. Patients with EPs also had significantly higher mortality risk (adjusted HR 1.70; 95% CI 1.56-1.84). Conclusion: In a large cohort of patients diagnosed with CRC, we found EPs to be common and independently associated with worse cancer outcomes. EPs also increased during the COVID-19 pandemic. Interventions are needed to reduce potentially avoidable EPs and improve outcomes of patients with CRC diagnosis.