Abstract : A sedentary lifestyle is a single factor for various metabolic diseases. The aim of this study was to determine the prevalence of sedentary lifestyles and its effects on weight and Body Mass Index (BMI) in female university students in Banda Aceh, Indonesia. This study was a cross-sectional study. A survey using a questionnaire was carried out on 865 female university students of Universitas Syiah Kuala and aged between 17-19 years. All participants were measured weight and height. Data analysis was using descriptive statistics and independent sample t-tests (p<0.05). In the total of 865 female students, the sedentary lifestyles were 38.61% and non-sedentary 61.39%. There was a significant difference between body weight (p=0.001) and Body Mass Index (BMI) (p=0.003) between the sedentary and non-sedentary groups. Common types of physical activity are walking as much as 71%, gymnastics around 19% and Jogging 10%. The highest frequency of physical activity per week is as much as 2 times/week with 39%, 3 times/week as much as 37%, and >3 times/week by 24%. The duration of physical activity that was mostly done by female students in Banda Aceh was <30 minutes by 47%, 30-35 minutes by 40%), and 60 minutes by 7% and >60 minutes by 5%. The prevalence of sedentary and non-sedentary was 38.61% and 61.39%. The prevalence rate of sedentary lifestyle is higher than Indonesia's national prevalence rate. A sedentary lifestyle is an influence on weight gain and BMI in female university students in Banda Aceh, Indonesia