Further progress in the development of modern gas turbines for aircraft engines and electric power stations requires both continuous optimization on component and system level as well as the use of new and innovative technology. Thereby, the design is often pushed closer to the physical limits, which demands an outstanding understanding and predictability of the structural behavior under different design and off-design conditions. Due to the considerable costs of real component testing, the knowledge on structural behavior and failure mechanisms of gas turbine components is often gained from validated numerical models. To obtain a realistic computational image of reality, the uncertainties inherent in the design, the material properties, the loading and the operation conditions have to be considered in the modeling process. The effect of variations in key input design parameters on critical results such as the predicted component life can be evaluated on the basis of probabilistic analyses. The paper addresses first general aspects of applying probabilistic Finite-Element analyses in the turbine blade design process. Then, probabilistic design methods are applied to investigate the lifetime of a single crystal (SX) turbine blade submodel. Thereby, variations in three SX orientations as well as different load positions and variations in the creep properties are investigated by Monte-Carlo-Simulation (MCS) techniques.Copyright © 2009 by Rolls-Royce Deutschland Ltd. & Co. KG