In pavement design, traditional empirical catalog methods leave their place to next generation mechanistic-empirical (M-E) design methods that utilize cracking, faulting and roughness as pavement performance parameters. Within the scope of this study, the effects of different traffic, subgrade and concrete strength classes for 20 and 40 year's service periods on the thickness and joint spacing of JPCP are determined by M-E design method for ten regions representing different climatic classes. A total of 360 rigid pavement designs are made for three traffic volumes, three subgrade types and two concrete strength classes for each region. As a result, the effects of subgrade type, traffic volume and concrete strength class on slab thickness and joint spacing is clearly identified for different climatic conditions. In addition, the joint spacing, which is predicted based on experience and observations in the in AASHTO 93 empirical method, can be successfully determined by M-E design method. This is especially advantageous for countries without rigid pavement experience like our country. Another output of this study is that M-E method makes it possible to use more innovative materials in the construction of rigid pavements since the material properties of the concrete slab have significant effects on the design.