This paper presents an evaluation of the performance degradation of Photovoltaic modules after few operation years in a tropical environment. To this end, the International Center for Research and Training in solar energy at Dakar University and the Lasquo-ISTIA laboratory of Angers University have put in place a research project in order to investigate the impact of the tropical climatic conditions on the PV modules characteristics. Accordingly, two monocrystalline-silicon (mc-Si) PV modules and two polycrystalline- silicon (pc-Si) PV modules are installed at Dakar in Senegal and monitored during a few operation years: Module A (16 months), Module B (41 months), Module C (48 months) and Module D (48 months). After few operation years under tropical environment, the global degradation and the degradation rate of electrical characteristics such as I-V and P-V curves, open-circuit voltage (V-oc), short-circuit current (I-sc), maximum ouput current (I-max), maximum output voltage (V-max), maximum power output (P-max) and fill factor (FF) are evaluate at standard test conditions (STC). This study reports on data collected from 4 distinct mono- and poly-crystalline modules deployed at Dakar University in Senegal. The study has shown that P-max, I-max, I-sc and FF are the most degraded performance characteristics for all PV modules. The maximum power output (P-max) presents the highest loss that can be from 0.22%/year to 2.96%/year. However, the open-circuit voltage (V-oc) is not degraded after these few exposition years for all studied PV modules. (C) 2014 Elsevier Ltd. All rights reserved.