Abstract : In recent years’ obesity has become a major health problem across all age groups. The life style changes and habits aggravated the prevalence of obesity especially childhood obesity. Many studies have suggested that serotonin has been linked with the occurrence of obesity along with various other factors. The serotonin transporter gene (SLC6A4) studies have been increasing in the recent time and based on these we aimed to study the relation of serotonin allele’s expression with Body mass index of university students. The study was a case control involving 66 participants done in Biochemistry department, RAK Medical and Health Sciences University, Ras Al Khamiah. Using a standardized questionnaire, the diet history was taken and using this we calculated the calorie intake. The saliva was collected and using the manufactures guidelines the DNA has been extracted using DNA Genotek kit. The polymerase chain reaction used to detect the polymorphism in the subjects using forward and reverse primers. Finally, DNA gel electrophoresis done to detect the alleles in different subjects. The study results showed that BMI, Waist circumference and body weight percentage was significant in overweight and obese subjects. The most common alleles in normal subjects was SS when compared with overweight and obese showing SL, LL. Our study was in accordance with other studies which showed L allele associate with obesity. There were some other showed contrary results which we didn’t find in present study. We suggest that, L allele associate is a risk and can be used to asses/predict the obesity.