This study examined the lifestyle factors which influence body weight and their relationship with major oral diseases among workers at Seventh-day Adventist institutions in Kigali, Rwanda. Furthermore, this study also explored whether lifestyle factors are related with dental caries and periodontal diseases. Research questions included: (1) What are the body weight and oral health status of workers in Seventh- day Adventist (SDA) institutions in Kigali, Rwanda?; (2) What is the lifestyle of workers in SDA institutions in Kigali, Rwanda in terms of a) diet?, b) physical activity?, and c) stress?; (3) Which of the lifestyle factors (diet, physical activity, and stress) significantly influence(s) body weight among workers in SDA institutions in Kigali, Rwanda?; (4) Is there a significant relationship between body weight and oral health status of workers in SDA institutions in Kigali, Rwanda? Methodology. A descriptive-correlation research design was used in this study. Data were collected using questionnaires, measurement of BMI, periodontal and caries index. Using the SPSS software, Pearson product-moment and Chi Square, correlations were computed to link factors that influence body weigh with oral health status. Results. Workers at Seventh-Day Adventist Church institutions in Kigali, Rwanda were generally overweight, the oral status showed high prevalence of caries and gingivitis affecting 67% of the participants. Diet (insufficient consumption of fruits and vegetables in terms of amount and frequency, poor choices and intake of quality dietary fats, and high consumption of starchy foods) and physical activity significantly influenced body weight while body weight and oral health status showed no significant relationship. Implications: Changes in the lifestyle factors that influence body weight need to be addressed. There is a need for leaders of the Seventh-day Adventist Church institutions in Kigali, Rwanda to plan and organize programs to promote awareness and lifestyle changes for their workers, particularly on healthy diet and regular physical activity and exercise. Moreover, health programs may include good oral health practices emphasizing the role of carbohydrates and sugar in the diet in order to prevent oral and chronic diseases.