Block type quay walls are one of the most generally used type of gravity quay walls however seismic risks of this kind of structures have not already received the proper amount of attention. In this study, stability of block type quay wall which consists of two concrete blocks is investigated experimentally and numerically. 1 g shaking table tests are used for experimental study. Model scale is 1/10 and model is placed on rigid bed to ignore damage due to foundation deformation. Two different granular materials (Soil 1 and Soil 2) which have different nominal diameters are used as backfill materials to understand the effect of nominal diameters on structure's stability. During the experiments accelerations, pore pressures, soil pressures and displacements are measured for two blocks under different cycling loadings. Soil pressure test results are presented in non-fluctuating and fluctuating components to determine the distribution and application point of the fluctuating component on two blocks. By using experiment results, the friction coefficients between the rubble-block and block-block are determined and compared with recommended friction coefficients in standards. PLAXIS V8.2 software program is used for numerical study to determine the material properties. (C) 2014 Elsevier Ltd. All rights reserved.