Abstract : Leptin is an ob (obesity) gene, a fat tissue determined hormone that assumes the main role in the guideline of muscle versus fat mass by regulating hunger and digestion while adjusting vitality admission and use. The objective of this study was to assess the conceivable relationship between serum leptin levels, lipid profile and Body Mass Index (BMI) between smokers and nonsmokers. One-hundred and eight subjects of 18 to 26 years males of ASU students were randomly chosen in this study. The subjects were grouped according to smoking criteria (53 smokers and 55 nonsmokers). After a complete assessment, statistical information was recorded and BMI. Fasting blood tests were attracted to quantify serum leptin, serum glucose, and triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and Cholesterol levels. The significance of the measured values and their correlation and regression (p and r) with the smoking habit using SPSS package version 22 were calculated. Serum leptin levels and differences between smokers and nonsmokers were not significant. The mean values for smoker leptin were 10.52 ±9.79 ng/ml and 11.17±9.09 ng/ml for non-smokers. The leptin levels were highly significant at (p<0.001) with BMI and subject weight, the leptin level of subjects with BMI (30 to 34.9) was 23.61±2.05 ng/ml and 28.45±1.2 ng /ml in those of BMI >35. The levels of serum leptin for non-smokers and smokers are not significant regardless of being on the borderline of the upper value of 9.2, whereas, leptin levels expand with BMI in overweight and obese subjects compared to normal BMI (18.5-25)