Probability based stability analysis is of rising prevalence in dam safety aroundthe world, though it is most commonly used for concrete structures. The stability of a Swedishrockfill dam has been analyzed with deterministic and probabilistic stability analyses. The probabilisticanalysis was made using the Rosenblueth method (point estimation method), where thesafety factor and reliability index β has been calculated for circular slip surfaces. A comparisonbetween deterministic and probabilistic stability analysis concludes that reliability-based stabilityanalysis is a useful method for integrating uncertainties into a stability analysis. However, itin our opinion is more suitable as a complement to deterministic analysis rather than as areplacement. High quality material data and a deep understanding of both geotechnical engineeringand probability theory is essential for reliability index β to be useful.