ABSTRACT: In the case of repairing castles, churches, baths and other monuments of Byzantine period there is often need of reconstruction of masonry members to reinstate the integrity of the complex. Then, bricks of specific dimensions color and morphology (for example 30*40*3 or 5 cm) should be ordered and manufactured. However, the modern process of preparing and firing the bricks is very different from the old one and the new ordered bricks differ considerably from the old bricks in terms of their properties and behavior. To understand the differences an experimental work was carried out. Brick plates of the above mentioned dimensions were produced without any machine pressure, following the traditional way, and were burnt at three temperature regimes 800,900 and 1000°C. After firing the mechanical characteristics such as compressive and flexural strength, modulus of elasticity have been determined by applying crushing tests as well as indirect measurements by sonometer. In parallel, samples from compact modern bricks produced after pressing and firing at 1200-1400°C were also tested similarly for comparison reasons. The results have shown that the modern compact bricks are heavier and their compressive strength is 4 or 5 times higher than that of old bricks. The modulus of elasticity of modern bricks is much higher than that of low temperature burning traditional bricks. The relationships between mechanical characteristics are also calculated and commented. The aim of the paper is to highlight the differences between old and modern bricks so as the restorers to be able to describe better the specific bricks required for intervention.