Tehran University of Medical Sciences Journal of Family and Reproductive Health 1735-8949 10 1 2016 05 15 9 14 EN Zahra Boroumandfar Infectious Diseases and Tropical Medicine Research Center, Isfahan University of Medical Sciences, Isfahan, Iran Farzin Khorvash Nosocomial Infection Research Center, Department of Infectious Diseases, Medical School, Isfahan University of Medical Sciences, Isfahan, Iran Katayoun Taeri Behavioral Disease Council Center, Isfahan University of Medical Sciences, Isfahan, Iran Mahrdad Salehi Psychosomatic Research Center, Isfahan University of Medical Sciences, Isfahan, Iran Ghasem Yadegarfar Department of Epidemiology and Biostatistics, School of Health, and Heart Failure Research Center, Isfahan University of Medical Sciences, Isfahan, Iran 2015 12 20 2016 03 16 Objective: The study aimed to design and evaluate the content and face validity, and reliability of knowledge, attitude, and behavior questionnaire on preventive behaviors among vulnerable women concerning sexually transmitted diseases (STDs). Materials and methods: This cross-sectional study was carried out in two phases of an action research. In the first phase, to explain STDs preventive domains, 20 semi- structured interviews were conducted with the vulnerable women, residing at women prison and women referred to counseling centers. After analyzing content of interviews, three domains were identified: improve their knowledge, modify their attitude and change their behaviors. In the second phase, the questionnaire was designed and tested in a pilot study. Then, its content validity was evaluated. Face validity and reliability of the questionnaire were assessed by test re- test method and Cronbach alpha respectively. Results: Index of content validity in each three domain of the questionnaire (knowledge, attitude and behavior concerning STDs) was obtained over 0.6. Overall content validity index was 0.86 in all three domains of the questionnaire. The Cronbach’s alpha as reliability of questionnaire was 0.80 for knowledge, 0.79 for attitude and 0.85 for behavior. Conclusion: The results showed that the designed questionnaire was a valid and reliable tool to measure knowledge, attitude and behavior of vulnerable women, predisposed to risk of STDs. https://jfrh.tums.ac.ir/index.php/jfrh/article/view/364 https://jfrh.tums.ac.ir/index.php/jfrh/article/download/364/343