In this paper we propose an observer-based Model Predictive Control strategy for solar trough plants. The controller has been tested at the parabolic-trough field ACUREX at the Plataforma Solar de Almeria (PSA). Results of the tests carried out at the plant are presented. Furthermore, the performance of the proposed control strategy is compared to a Gain-Scheduling Generalized Predictive controller and a PID controller. (C) 2013 Elsevier Ltd. All rights reserved.