In this paper, stochastic and deterministic dynamic responses of gravity dam-reservoir systems are compared using the displacement fluid finite elements. For stochastic dynamic analysis of gravity dam-reservoir systems, variable-number-nodes two-dimensional fluid finite elements based on the Lagrangian approach is programmed in FORTRAN language and incorporated into a general-purpose computer program, which is used for stochastic dynamic analysis of solid systems, STOCAL. The Sariyar concrete gravity dam, constructed in Turkey is selected for numerical example. The S16E component recorded at Pacoima dam during the San Fernando Earthquake in 1971 is used as a ground motion. Displacements and hydrodynamic pressures occurring on the upstream face of the dam and stresses occurring on the dam section are calculated by using stochastic and deterministic methods and compared with each other. (c) 2005 Elsevier B.V. All rights reserved.