The main objective of this paper is to analyze the competitiveness of the main maritime Port sited in Portugal - Port of Sines. This paper is developed under the Resource-based view approach. A literature review about the Resource-based view is presented with a special highlight on the contribution of organizations owns’ resources to the competitiveness. With this paper we intend to emphasize the applicability of a management theory to a different type of organizations which only recently start to be preoccupied with its competitiveness. A case study methodology is used in order to collect all the information needed about its main resources and capabilities of Port and also its competitiveness. The resources analysed in this paper are: the infrastructures, the accessibilities, the Port operations and also the information systems used on it. Also, a set of performance data is analysed as the main indicators of competitiveness. After that, a conceptual model is presented in order to systematise the main resources and capabilities under which the competitiveness of the Port of Sines is built on.