This paper presents a numerical investigation of the behavior of stiffened steel panels, accounting for different configurations of the Passive Fire Protection (PFP) layer, under fire conditions. In the simulations, nominal temperature-time curves, as well as variations in mechanical and thermal properties of steel due to temperature, determined by EUROCODE1 and 3 [EC1 e EC3] (2004) were used, and a shell finite element model was developed using ABAQUS® commercial software. The thermal and mechanical analyses were decoupled; therefore, the transient temperature field due to fire was first assessed and, then, this thermal load was applied to the structure for the evaluation of its mechanical behavior. The initial geometry of the model took into account the initial imperfections recommended by ISSC (2012). The fire conditions were assumed as a result of a typical process involving combustion of hydrocarbons. Once the fire scenario was set, it was possible to assess the development of the temperature field with respect to time. Induced thermal loads were taken into account in the analysis of the structural model in combination with the pre-existing operating loads, thereby allowing the evaluation of the panel behavior. The purpose of this paper is to present the methodology employed to assess a steel ship structure in case of fire, which can be generalized to represent diverse conditions. The results show that the use of protective materials delays fire heating, improving its behavior during the fire. The choice of the best PFP solution depends on the load case and panel configuration. Finally, it is concluded that the methodology employed in this study can be used in the optimization process of the PFP layer. © 2013 Taylor & Francis Group.