OBJECTIVE:Although recent screening guidelines recommend annual fecal occult blood testing (FOBT) for adults aged > or = 50, a number of studies report that these tests are underused. Systematic efforts to increase awareness of colorectal cancer (CRC) and to promote screening participation are needed to meet national objectives for CRC control. METHODS:This study examined CRC-screening practices and evaluated factors related to recent participation in screening by FOBT in a sample of women aged 50 to 80 who were surveyed about their use of clinical preventive services at Group Health Cooperative, a managed care organization in western Washington State. RESULTS:Of the 931 women eligible for analysis, 75% reported ever having been screened by FOBT and 48% reported having been screened within 2 years before the survey. Participation in screening did not vary by demographic characteristics or by perceived or actual risk of CRC. Women with a positive attitudes toward CRC screening had sevenfold greater odds of recent screening by FOBT (odds ratio=7.1; 95% confidence interval, 4.4 to 11.6). Only 58% of study women reported that their physicians encouraged CRC screening, but this factor was strongly related to participation (odds ratio=12.7; 95% confidence interval, 6.6 to 24.4). CONCLUSIONS:We identified several areas in which understanding of CRC risk may be low. As a whole, these findings suggest that effective strategies to control CRC may include efforts to improve knowledge of risk and prevention, but must also appeal directly to primary care physicians to identify and address their barriers to screening recommendations.