Production of bitumen from tar sands requires heating the reservoir to several degrees of magnitude to reduce the viscosity of the bitumen. Proper characterization of viscosity property of this fluid is necessary for the designing and optimization of recovery methods. In this work, tar sand samples were collected from different locations in the Ore axis of Ondo state. Bitumen were extracted from the tar sands. The effect of temperature on the viscosity of each sample were measured using an NDJ-8S digital viscometer at temperature ranging from 122-374°F. Viscosity behaviour were different from location to location and they typically reduced as temperature increased. Viscosity measurement varied from 876,000cp – 5,200cp as temperature increased from 122-374°F. Some samples showed higher viscosity profile than other sample. Therefore, higher temperature and energy requirement is needed for the recovery process of these Nigeria Reservoirs.