Most cases with colorectal cancer (CRC) have been historically reported in older age population. There have been documented observations, however, on the rise of number of patients presenting with CRC at earlier-than-expected age. The national cancer institute Surveillance, Epidemiology, and End Results (SEER) program provides an opportunity for tracking trends of different cancer diagnoses in the US over time as it has been compiling data from different US registries since 1975. We used data from SEER to explore real-world trends in CRC diagnosis at young age using different cutoffs for defining early onset disease. Moreover, we compared stage and survival data between patients with early onset and late onset disease. Using SEER Research Database (8 reg; Nov 2021 Submission), we included cases diagnosed with CRC between 1975 and 2015 with complete relevant clinical data. Data including age at diagnosis, year at diagnosis, summary stage, and survival were exported to SPSS where Chi-Square test and Log-rang test were used to explore statistical significance for potential comparisons. We used different cutoffs for defining early-onset including age <30, age <40, age <45, and age <50. Upon analyzing 423,069 cases diagnosed between 1975 and 2015, there is a substantial increase in the proportion of cases diagnosed with CRC at younger age populations using different cutoffs for defining early-onset disease (Table). Patients diagnosed at earlier age were more likely to have distant metastasis compared to patients with older age at diagnosis regardless of the used age cutoff (all p < 0.05). However, overall survival was significantly longer in patients with early-onset disease compared to those with late-onset (all p < 0.05).Table: 325P1975-19841985-19941995-20042005+Age < 300.3%0.3%0.4%0.6%Age < 401.6%1.8%2.2%2.8%Age < 453.1%3.5%4.5%5.7%Age < 505.8%6.2%8.5%10.9% Open table in a new tab There is a substantial increase in the proportion of cases with CRC diagnosed at young age who are more likely to present with distant spread compared to cases diagnosed at old age. However, overall survival remains higher in this age population.