摘要:Background: Colorectal cancer (CRC) is the third most common malignancy in Iran. Limited data are available on knowledge and barriers in regard to CRC and screening tests in Iran. The aim of the study was to characterize knowledge, practice, and barriers toward CRC and its screening tests among an Iranian at-risk population. Methods: This cross-sectional study was conducted with participation of 200 individuals of both genders aged 50 years or older in a teaching hospital in Tehran, Iran. Data were collected via face-to-face interviews. A questionnaire containing demographics; knowledge about CRC and screening tests; screening practice; and reasons for not being screened was administered. The reliability alpha for knowledge items was 0.52. Results: The age of the participants ranged from 50 to 83 years (mean 60.13). Overall, 11% of the respondents reported prior screening by either fecal occult blood test (6.5%) or colonoscopy (4.5%). The majority of individuals had poor knowledge although respondents with prior screening obtained slightly higher score in comparison with nonparticipants in screening (26.74 vs. 23.24; P <0.05). Four commonly cited reasons for not having CRC tests were “doctor did not recommend the test,” “did not think it was needed,” “never think of the test,” and “no symptoms/problems” which were reported by 29%, 26%, 20%, and 17% of the participants, respectively. Conclusion: It is necessary to design appropriate educational interventions to increase the general population's knowledge about CRC and screening before implementing preventive programs in Iran.