Bricks are widely used in building construction as the most common building materials in Iran. The heavy weight of bricks causes the great mass of construction and thus more vulnerability against earthquake forces. It is therefore tried to reduce the density of the bricks, as well as improve thermal insulation properties. Polystyrene foam is one of the substances that are added to the raw materials of bricks, as a pore-forming material. The effect of PSF type and its content in the mix, and also the firing temperature of the bricks on density, water absorption and compressive strength, are investigated and discussed in this paper.