Background: Increasing colorectal cancer screening (CRCS) is important for attaining the Healthy People 2020 goal of reducing CRC-related morbidity and mortality. Evaluating CRCS trends can help identify shifts in CRCS, and specific groups that might be targeted for CRCS. Methods: We utilized medical records to describe population-based adherence to average-risk CRCS guidelines from 1997 to 2008 in Olmsted County, MN. CRCS trends were analyzed overall and by gender, age, and adherence to screening mammography (women only). We also carried out an analysis to examine whether CRCS is being initiated at the recommended age of 50. Results: From 1997 to 2008, the size of the total eligible sample ranged from 20,585 to 21,468 people. CRCS increased from 22% to 65% for women and from 17% to 59% for men (P < 0.001 for both) between 1997 and 2008. CRCS among women current with mammography screening increased from 26% to 74%, and this group was more likely to be adherent to CRCS than all other subgroups analyzed (P < 0.001).The mean ages of screening initiation were stable throughout the study period, with a mean age of 55 years among both men and women in 2008. Conclusion: Although overall CRCS tripled during the study period, there is still room for improvement. Impact: Working to decrease the age at first screening, exploration of gender differences in screening behavior, and targeting women adherent to mammography but not to CRCS seem warranted.