Due to increasing demand, gas supply is one of the most strategic energy security issues for huge importers. By taking this into consideration, Caspian region -where important gas supply potentials exist- is directly related with the huge importers' energy security issues, mainly which are EU, China, India and Turkey. As an important gas supplier country locating in Caspian Region, Turkmenistan and her future gas supplies are becoming more important for the importers above. As a result, each importer is preparing long term plans and developing new projects to import the gas resources from Turkmenistan. One of the most popular projects -related with Turkmen gas resources- is Trans Caspian gas pipeline, which is planned to transport Turkmen gas through Caspian Sea to Azerbaijan and then with other available pipelines to Turkey and Europe. Naturally, this pipeline is an important energy security issue for Turkey-Azerbaijan and EU. However, there are important political, technical and economic milestones to consider. In this study, after having a short outlook into the gas politics in the Caspian Region -mainly Turkmenistan related issues-; importance of Trans Caspian gas pipeline project will be described. Then, doability of this popular project will be evaluated from the technical-political and economic perspectives. Additionally, Iran's claim to transport Turkmen gas through Iran to Turkey instead of Trans Caspian project will economically be compared.