A series of experiments were conducted to study the potential effect of temperature on wettability of a carbonate reservoir using contact angle measurement method. Natural core plugs which were originally drilled out of the formation, were further cut into disk-shaped core samples in order to mount them inside a custom made cell which was designed to run the high temperature and high pressure experiments. This proprietary cell was designed to hold a solid core wafers and equipped with an injection needle to create a droplet on the surface of the wafer. Having made a droplet of oil on the surface of the core sample, the temperature was ramped to elevated temperatures and the contact angles were measured continuously at certain time intervals. Experiments were conducted on both natural cores and toluene-extracted core samples.