In this study, Newlands coal, spirulina microalgae samples, and mixtures of them were gasified in a fixed-bed downdraft reactor by CO2 at the atmospheric pressure and in the temperature range of 950-1000 degrees C. The effects of the reaction temperature, the CO2 partial pressure, and the blending ratio on the syngas yield were studied. Results showed that the CO2 partial pressure did not affect the gas production yield until its value exceeded 0.05 MPa. The cogasification experimental results showed higher values than the predicted ones in terms of the gas production yield, especially H-2 and CO components when the blending ratio of algae is 50% wt. This synergetic effect was mainly attributed to the catalytic activity of the high content of alkali and alkaline metals in algae. The increase of the reaction temperature led to a higher gas production yield as the Boudouard reaction is an endothermic reaction that went to a higher extent with the temperature increase.