Background: The purpose of the study was to assess changes in total cholesterol, LDL-C, HDL-C, non HDL-C and triglyceride levels over a 3-year period in subjects enrolled in the Tehran Lipid and Glucose Study. Materials and methods: A total of 1839 males and 2553 females, aged 3 years and over, were included in this study. Baseline demographic characteristics and lipid levels were determined GTT was performed at baseline and after 3 years in subjects ≥20 years age. Results: In both sexes, BMI and WHR,(waist-hip ratio), increased significantly from baseline. Mean BMI at baseline was 24.7±5.8, which in phase 2, rose to 26.0±5.6 kg/m2 (p=0.001). In phase one, 32 and 18.6% of all subjects and in phase two, 34 and 23.4% respectively were overweight and obese (p=0.05). Prevalence of impaired glucose tolerance, (IGT), and Diabetes mellitus increased in phase 2 of the study. 13% of all subjects in phase 1 had IGT and 11.4% had diabetes these statistics increased to 14.2 and 12.3% respectively in phase 2. In phase 2, systolic and diastolic blood pressure, mean cholesterol, LDL-C, HDL-C, non HDL-C and triglycerides decreased significantly from baseline levels. In phases one and two, 5.1% and 7.6% of subjects respectively were unaware of their diabetes. Conclusion: There is a high prevalence of cardiovascular risk factors, such as overweight, obesity, low HDL-C, IGT and diabetes in the urban population of Tehran. It was seen that although mean total cholesterol, LDL-C, non-HDL-C, TG, SBP and DBP decreased significantly after 3 years, IGT, DM, overweight, obesity and Low HDL-C increased from baseline values.