The urgent requirement to optimize the consumption of energetic resources justifies the application of advanced control strategies to automate equipment that consumes higher amounts of fossil fuels, among them the fire-tube boilers. From a control engineering point of view, these systems are characterized by a difficult dynamic behavior, multiple inputs and outputs, time delay and several uncertainties. In this work an advanced control system with an Adaptive-GPC algorithm of the steam pressure inside a fire-tube boiler is presented. System identification techniques were employed to obtain a mathematical model that characterizes the dynamic behavior of the process under study. Simulation results evidenced that this model describes with high exactitude the process of steam pressure variation inside the boiler. The model obtained was subsequently used to design the advanced control system. The system was implemented in a utility fire-tube boiler and the results showed its efficiency to deal with variations of the dynamic parameters of the process arisen at different operating conditions. It also showed its superiority against a control system using a PID algorithm. Copyright © 2007 International Federation of Automatic Control All Rights Reserved.