Abstract Introduction: Colorectal cancer (CRC) is a leading cause of cancer-related death in the United States. While CRC-specific mortality has been decreasing, significant disparities by race/ethnicity and socioeconomic factors persist. Unfortunately, despite evidence that CRC screening and early detection are cost effective and reduce incidence and mortality, less than 2/3 of age-eligible adults meet screening guidelines. Research has consistently shown that patients who are insured by Medicaid or are uninsured are even less likely to be screened than those who are privately insured. However, while much research treats insurance status as a stable factor, many low income people cycle on and off insurance. Thus, studies may oversimplify the association between insurance status and preventive care. Our goal in this analysis is to describe how patient demographic characteristics, specifically the varied experience of insurance, are associated with CRC screening rates in “real world” settings. Methods: We analyzed baseline data from patients in four urban federally qualified health centers participating in a randomized controlled trial to promote CRC screening. These in-person interviewer-administered surveys included items on socioeconomic factors, healthcare, and screening utilization. We examined bivariate associations to determine differences in past screening utilization. Patients were defined as screening “up-to-date” if they had received a fecal occult blood test in the past year and/or a flexible sigmoidoscopy or colonoscopy within the past 5 years. Based on current screening guidelines, we excluded people under the age of 50 from our analysis. Of the 329 patients surveyed across the 4 centers, 289 (87.8%) were age ≥50 and were included in this analysis. Results: Of these 289 patients, 115 (39.8%) met the criteria for being screening up-to-date. The sample had slightly more females than males (54.3% vs. 45.7%) and was primarily African-American (84.4%). Initial results show statistically significant demographic differences by screening status (p<0.05). The up-to-date patients were older (mean age, 57 vs. 55), and more likely to be female (64.1% vs. 46.9%), have a personal healthcare provider (95.7% vs. 67.2%) and feel “very” or “extremely” comfortable discussing CRC screenings with a primary care doctor (92.3% vs. 75.6%) than patients who were not up-to-date. Additionally, up-to-date patients were less likely to have been homeless in the past 12 months (12.8% vs 31.1%) and less likely to have put off healthcare needs in the past 12 months due to cost concerns (24.8% vs 41.2%) or lack of transportation (17.9% vs. 28.8%). We saw no significant differences in screening status by education level or race. Up-to-date patients were significantly more likely to be currently insured (86.3% vs. 61.9%) than not up-to-date patients. Among those insured (n=210; 71.4%), up-to-date patients were less likely to have had a period without insurance in the past 12 months (19.8% vs. 33.9%) and had different distributions of insurance type than not up-to-date patients. Discussion: Less than 40% of age-eligible patients were screening up-to-date in our study. Examining differences between up-to-date and not up-to-date patient populations can provide insight into what factors might be important in promoting CRC screening in medically underserved populations. Our preliminary findings indicate that insurance stability might play a positive role in CRC screening adherence. Statistical modeling might better characterize the role of insurance in screening. Researchers might consider the nuances of measuring insurance and the stability of insurance when studying the association between insurance status and healthcare utilization. In addition to guiding future research, these findings could drive future politico-structural improvements to health care policy. Citation Format: Kunal M. Mathur, Meera Muthukrishnan, Graham A. Colditz, Aimee S. James. Insurance “instability” and colorectal cancer screening utilization. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr C10.