Olive samples used in this study were supplied from different Turkish olive species. Olive cake is a waste from olive oil production process. Turkey produces 8.41% of the total olive in the world. Olive cake can be pyrolyzed into bio-oil. The yield of bio-oil first increases and then decreases as a function of temperature. Therefore, there is an optimum temperature for pyrolysis from olive cake into bio-oil. The maximum yield for olive cakes is 40.5% at 650 K. The liquid fraction of the pyrolysis products consists of two phases: an aqueous oily phase containing a wide variety of organo-oxygen compounds of low molecular weight and a non-aqueous tarry materials phase containing insoluble organics (mainly aromatics) of high molecular weight.