An Information Architecture is the basis for a comprehensive and integrated information system of any organization, capable of providing answers that meet the challenges posed by the contemporary competitive environment. In this paper we analyse a number of representative methodologies used in Information Architecture definitions and, based on a set of pre-defined criteria, we select the Adapted BSP (Business Systems Planning) Methodology to apply in a local public administration organization in Portugal. This methodology proved to be sufficiently flexible and suited to the goals proposed.