A C60 fullerene/tetracene adduct was synthesized and studied by electronic absorption spectroscopy and FT-IR spectroscopy. Essentially the mono-adduct was obtained as suggested by the spectroscopic analysis and by the thermogravimetric analysis (TGA). The stability and the retro Diels-Alder reaction of the C60/tetracene adduct was studied by TGA, differential thermogravimetric analysis (DTG) and by differential scanning calorimetry (DSC). It was found that the adduct is stable above 300°C and decomposes at 323-390 °C according to the DSC analysis. The decomposition involves the release of tetracene and the restoration of C60 in high yields. However, part of the C60 is lost as amorphous carbon in the retro Diels-Alder reaction.