In the recent years it has been noted a rapid groath of video games with large or theoreticaly infinite open worlds and also a dramatic decrease of the available time for their production. These tow conditions have driven into the import and intergration of automated technices of design, like procedural content generation. This dissertation studies the use of this technic through the prism of video games. The general frame of the study is established through the explenation of the terms of procedural generation, the relations with the different scientific fields and a brief historical retrospective of the video game industry. Subsequently the frame of study narrows down at the importance of space in video games and the different aproaches that are used for their creaton, in order to clearly define the parameters that make the produced result indentify as procedurally generated. One of the two main cores of this dissertation are the programming grammars with emphasis in the shape grammars and their interaction with graph grammars for the production of diagrams of interations and spaces and their use is furthermore examined through the analysis of the way of world creaton in Minecraft. The second basic core includes the game engines Tanagra and Launchpad, that are the most prominent examples of mixed initiative engines, as well as manner of interaction of the physical designer with the program. The result of this interaction is the game Endless Web and its analysis as a peciment of procedural generation based game. The study finally concludes that procedural generation is a new design methodology with descrete characteristics that are focused on the programmatic nature of design as well as the interaction of the physical designer and the program.