摘要:Background: Clinical guidelines have increasingly been used as tools for applying new knowledge and research findings. Although, efforts have been made to produce clinical guidelines in Iran, it is not clear whether they have been used by physicians and what factors are associated with them?. Methods: Four hundred and forty three practicing physicians in Tehran were selected from private clinics through weighted random sampling. The data collection tool was a questionnaire on familiarity and attitude toward clinical guidelines. The descriptive and analytical findings were analyzed with t -tests, Chi2, logistic and linear multivariate regression by SPSS, version 16. Results: 31.8% of physicians were familiar with clinical guidelines. Based on the logistic regression model physicians’ familiarity with clinical guidelines was positively and significantly associated with ‘working experience in a health service delivery point’ OR = 2.13 (95% CI, 1.17-3.90), ‘familiarity with therapeutic protocols’ OR = 2.09 (95% CI, 1.22-3.57) and ‘holding a specialty degree’ OR = 2.51 (95% CI, 1.24-5.07). The mean overall attitude scores in the ‘usefulness’, ‘reliability’, and ‘problems and barriers’ domains were, respectively, 78.9 (SD = 16.5), 78.9 (SD = 19.7) and 50.4 (SD = 15.9) out of a total of 100 scores in each domain. No significant association was observed between attitude domains and other independent variables using multivariate linear regression. Conclusions: Little familiarity with clinical guidelines may represent weakness in of production and distribution of domestic evidence. Although, physicians considered guidelines as useful and reliable tools, but problems such as difficult access to guidelines and lack of facilities to apply them were stated as well.