Poseidon Linux was designed as a friendly and complete desktop, based on open source software and aimed at the Brazilian/International scientific community. This operating system is based on Ubuntu and inspired by Quantian Linux. It offers several specific tools in the areas of GIS, 3D Visualization, Mathematics, Statistics and several otherfields of research. It also has all the software expected in a modern desktop such as an office suite - with spell checker, web browsers, e-mail readers, instant messaging, to cite but a few.