Background & Objective: The early identification of risk factors by screenings methods, as low-cost diagnostic tests with high survival rates, has always been of paramount importance for cancer diagnostics, especially in breast cancer. Since knowledge, attitude, and practice studies offer a desirable way to examine the status and make predictions, this study aims to design a valid and reliable instrument to assess breast cancer risk factors, symptoms, and screening methods.

Materials & Methods: The Waltz method was used to develop the questionnaire. The exploratory factor analysis with a sample size of 390 and the confirmatory factor analysis were carried out using Amos software and SPSS 22, respectively. The reliability of the instrument was also assessed on 30 women over a one-month interval using the Cronbach's alpha and test-retest method.
Results: The preliminary 87-item was finally developed into three sections: attitude (14 items and 2 factors with CVI=0.92, CVR= 0.72 and α= 0.76,) knowledge (16 items and 5 factors with CVI= 0.99, CVR= 0.85 and alpha 0.87) and practice checklist (8 items and CVI = 0.94 and CVR =1).
Conclusion: The results suggested desirable psychometric properties of the questionnaire and its strength and validity in evaluating knowledge, attitude, and practice for identifying factors influencing breast cancer.