Overweight and obesity is one of the health problems in the world. This condition is associated with various health problems such as cardiovascular disease, stroke, osteoarthritis, chronic back pain, gallbladder disease, and cancer. Consuming adequate fluids can help you lose weight. This study aimed to determine the relationship between body fluid intake and body mass index (BMI) in Medical Faculty Universitas Sumatera Utara students. A cross-sectional study was conducted on USU Medical Faculty students from October 2020 to January 2021 with a sample of 99 people. Researchers obtained primary data obtained through reporting daily fluid intake for seven consecutive days and anthropometric measurements. Furthermore, the researchers conducted the Spearman test to determine the relationship between the two variables. Based on the characteristics of the sample, the researchers obtained 51 samples that were female (51.5%), and 48 were male (48.5%) with an average age of 20.05±1.08 years. The average fluid intake consumed was around 2070.07±654.93 mL per day, whereas 48 people in the study sample consumed less fluid below 2000 mL/day (45.5%). The classification of nutritional status of the sample based on BMI showed that 44 people had normal nutritional status (44.4%), 48 people were overweight (48.5%), and seven people were obese (7.1%). The test results showed a significant relationship between daily fluid intake and BMI (p-value = 0.007).