Abstract: In life prediction of structural components containing an initial flaw it is particularly important to determine stress intensity factors (SIFs) to a high degree of accuracy. In the particular case of cracks emanating from cold worked holes a very important factor affecting the prediction of fatigue crack propagation is the aleatory variation of experimentally-derived residual stress distributions. This presentation will discuss a model of fatigue crack propagation and present results of simulations when uncertainties in the input residual stress distribution are considered. Life predictions are compared with experimental fatigue life data for aluminum alloys.