In this work, variation of the main electrical parameters of flexible organic light-emitting diodes (FOLEDs) is studied as a function of the thermal conditions. Tested structures are consisted of polyethylene terephthalate (PET) as a flexible substrate, indium-tin oxide transparent conductive anodes, polyphenylene vinylene derivative based emissive films and aluminum cathodes. Thermal degradation analysis of the FOLEDs characteristics is performed by IR thermography in broad range of voltages and driving current densities at different temperatures. The study of thermal distribution with the time provides important information for the thermal events in the operating FOLED, as well as for the local temperature change, due to the presence of hidden defects. CFD thermal simulations of two types of test FOLED samples were conducted. Experimental measurements of the distribution of surface temperature of the samples were carried out with an infrared camera. The obtained difference between the simulated and measured values is not greater than 5 °C at the beginning of degradation processes.