Tehran University of Medical Sciences Nursing Practice Today 2383-1154 10 2 2023 05 01 108 123 Samiha Sayed Department of Community Health Nursing, Faculty of Nursing, Damanhour University, Damanhour, Egypt AND Department of Public Health, College of Health Sciences, Saudi Electronic University, Riyadh, Saudi Arabia Sahar El-Sakkar Faculty of Nursing, Damanhour University, Damanhour, Egypt Sabreen Elsaka El-Beheria Governorate Ministry of Health and Population, Damanhour, Egypt Amira El-Houfey Department of Community Health Nursing, Faculty of Nursing, Assiut University, Assiut, Egypt 2023 02 04 2023 04 30 Background & Aim: The trans-theoretical model suggests that stage-matched interventions improve the effectiveness of behavior changes such as quitting. This study aims to examine the effect of stage-matched smoking cessation educational intervention based on the trans-theoretical model using motivational interviewing on Egyptian males' knowledge, stage movement, and smoking cessation rate. Methods & Materials: A randomized controlled trial was conducted in the main building of Damanhour University, Egypt. The participants were selected using simple random sampling (N=165), then allocated to both experimental (N=82) and control (N=83) groups using the randomization block technique. Data was collected using a structured interview schedule. The instrument contained five parts: Personal Characteristics and Smoking data, Fagerstrom Tolerance Questionnaire, Tobacco Cessation Readiness Scale, Smoking Knowledge Scale, and trans-theoretical Model constructs questionnaire. The experimental group received ten months of educational intervention using face-to-face and phone-based motivational interviewing. Results: A significantly higher stage movement was revealed among the experimental group post-intervention (80.5%); 35.4% transitioned to the preparation stage, 32.9% were in the action stage, and 12.2% were in the maintenance stage. According to the ANCOVA test, significant negative mean differences post-intervention was achieved for nicotine dependence and decision pros (P=0.000) with a large effect size (η2=0.341, η2=0.503). However, significant positive mean differences were proved for other variables (knowledge, tobacco cessation readiness, and TTM constructs) (P<0.05) with a large effect size (η2>0.14). Stage analysis revealed significant mean differences in most studied variables, where the action stage had the highest significant mean improvements (P<0.05). Conclusion: The trans-theoretical model-based educational intervention using motivational interviewing effectively improves smoking knowledge and facilitates quitting with successful stage movement among Egyptian male smokers. https://npt.tums.ac.ir/index.php/npt/article/view/2387 https://npt.tums.ac.ir/index.php/npt/article/download/2387/568