The design firms have fundamental responsibility and represent a fundamental link in the civil construction chain of production and the discussion about management of these firms, considering their limits and particular characteristics, aims promote actions to transform them effective organisations in this production environment. The information system is the component that connects all administrative process of a company, as the operational also the strategic. With regards it, this paper aims analysing and understanding the general information architecture of a design firm through the applying of method proposed by Turban; MacLean; Wetherbe (2004) called how “Information Requirement Analysis Planning Model “. Considering the paper authors experience about administrative and technical routines of these firms obtained through the research from 2006 to 2007, the model was applied at generic routines (administrative and technical) of medium and small design firms. The research was supported by a bibliography revision about Information System subject and is part of a master degree dissertation of one the authors. Key-words: design firms, management, information system.