Iran is a country with high seismicity while Tehran, the capital city is home to more than 10 million people which are located on the highest seismic zone of the country. There exist 153 gas stations throughout the metropolitan which are constructed to old building codes with little or no attention to the seismic considerations. In this study which was supported by the National Oil Company, first a site investigation of each station was conducted creating a seismic hazard map. A detail review of the existing drawings and creating as built drawings by opening different sections to control the original drawings then was conducted. After completing the as built drawings, a series of qualitative and quantitative investigations based on structural and finite element analysis was performed resulting in weak link identification for two performance criteria of life safety and immediate use levels. Based on the analytical investigations then deem-to-comply strengthening details and drawings were constructed. The whole procedures were utilized for the main building, piping and tanks, shed structure, pumps and mechanical and electrical units in each station. This paper will provide details in regards to the procedure, findings and retrofitting techniques which were used to achieve the goals of the project.