Regional magnitudes and patterns of Arctic winter climate changes inconsequence of regime changes of the North Atlantic Oscillation (NAO)are analyzed using a regional atmospheric climate model. The regionalmodel has been driven with data of positive and negative NAO phasesfrom a control simulation as well as from a time-dependent greenhousegas and aerosol scenario simulation. Both global model simulationsinclude a quite realistic interannual variability of the NAO withpronounced decadal regime changes and no or rather weak long-term NAOtrends. The results indicate that the effects of NAO regime changeson Arctic winter temperatures and precipitation are regionallysignificant over most of north-western Eurasia and parts of Greenland.In this regard, mean winter temperature variations of up to 6 K mayoccur over northern Europe. Precipitation and synoptic variabilityare also regionally modified by NAO regime changes, but not assignificant as temperatures. However, the climate changes associatedwith the NAO are in some regions clearly stronger than thoseattributed to enhanced greenhouse gases and aerosols, indicating thatprojected global changes of the atmospheric composition and internalcirculation changes are competing with each other in their importancefor the Arctic climate evolution in the near future. The knowledge ofthe future NAO trend on decadal and longer time scales appears to bevitally important in terms of a regional assessment of climatescenarios for the Arctic.