Background: Healthy diet behavior is one of the effective and modifiable factor for hypertension control. Aim of the study was conducted to evaluate the effect of application of trans-theoretical model on diet behavior modification among hypertensive employee in electrical Company. Design: A quasi-experimental design was used. Setting: The study was conducted at Benha Electrical Company in Benha City, Egypt. Sample: A purposive sample of 70 hypertensive employee in electrical company. Study instruments included two tools were used for data collection. The first: Structured interview questionnaire concerned with socio-demographic data and knowledge of employees about hypertension, Diet behavior modification and Trans theoretical model (TTM). The second: Trans- theoretical model of behavior changes questionnaire. Results: revealed that 14.3 % of studied sample had good knowledge pre TTM application compare to 81.4% of studied sample had good knowledge post TTM application for Diet behavior Knowledge. Besides, there was high significant positive correlation between total knowledge score and total score of stages of diet behavior changes (r = 0.76, p < 0.0001). Conclusion: The application of TTM of behavior change was control hypertension among hypertensive employee's was observed in decreasing measurement of blood pressure and increasing employees' self-efficacy, pros, experiential and behavioral processes of change while decreasing cons post application of TTM as compared to application of TTM. Recommendation: provide electrical company employees with web site for health information to improve their knowledge and diet behavior to control chronic diseases as hypertension