Abstract We present NMR relaxation experiments of water and oil confined in a series of calibrated porous media and natural rocks of different wettability, at various temperatures and magnetic fields. The longitudinal 1/T1 and transverse 1/T2 relaxation rates are interpreted with an original theoretical model which shows that the solid-liquid interactions occurring at the grain surface are responsible for the temperature dependence of the relaxation rates. For instance, 1/T1 and 1/T2 measured on water saturated samples of silica surfaces present an anomalous temperature behavior, contrary to the case of water in porous media with calcium carbonate surfaces. The relaxation rates of oil saturated porous media present always a normal temperature behavior for every surface. The temperature effect is not negligible for high reservoir temperature and should be taken into account or tested when calibrating log data using experiments performed at laboratory temperature.