A simulation with the Hamburg atmospheric generalcirculation model ECHAM-4, forced with sea surface temperatures of the period1950--1994 and with stable water isotopes H218Oand HDO explicitly included in the water cycle, was performed to examine interannualto decadal variations of the isotopic composition of precipitation in Greenlandand Antarctica. The analyses focus on the Summit region, central Greenland,and the Law Dome region, East Antarctica, respectively. Simulation resultsreveal that about one third of the simulated variability in H218Ocan be explained by simultaneous changes of the surface temperature at theprecipitation sites. Other climate variables influencing the isotope signalare identified by multiple linear regression, and the results show that theH218O record in central Greenland integratesthe climatic history of a broader region. For the Law Dome region in Antarcticathe H218O record appears to be mainly relatedto climate changes at the precipitation site only. For the deuterium excessa clear influence of climate condition at two distinct regions of the IndianOcean on the simulated deuterium excess record of the Law Dome region is found.On the contrary, a reconstruction of the year-to-year variability of the deuteriumexcess signal in central Greenland, by Atlantic Ocean surface parameters only,fails. Additional correlation analyses between the ECHAM-4 isotope simulationand indices of the North Atlantic Oscillation (NAO) and the El Ni¿o-SouthernOscillation phenomenon (ENSO) enable the detection of influenced regions inGreenland and Antarctica: While NAO and ENSO are imprinted in the simulatedH218O record of precipitation, they cannotbe detected in the simulated deuterium excess record.