Abstract: Temproral and spatial patterns of the Arctic seaice variations have been documented in this study with 44 year (1951-1994) monthly seaice concent ration dataset. A more objective season is defined for describing natural seasonal variations of the seaice, with winter in February-April, spring in May-July, summer in August-October and fall in November-January. According to such a definition, dominant patterns of the seaice anomalies in the extent are examined with EOF decomposition. It was found that key regions with large variability of seaice are locat ed in the Greenland and Barents Seas, the Davis Strait, the Bering Sea and the Sea of Okhotsk during winter, but confined to a zonal area along the Kara, Laptev, East Siberian and Beaufort Seas during summer. Dominant modes of seaice variability exhibit in phase fluctuations in most of the key regions during spring and fall, yet out of phase fluctuations between the western North Atlantic (the Greenland and Barents Seas) and the eastern North Atlantic (the Labrador Sea and the Davis Strait) together with t he North Pacific (the Bering Sea and the Sea of Okhotsk) during winter, and out of phase fluctuations between the East Siberian and Beaufort Seas and the Kara Sea during summer. The annual mean extent of the Arctic seaice is charact erized by a decadal-scale variation superimposed upon a long term diminishing trend over the 1951-1994 period, which is largely attributed to the dominant mode of spring (May-June-July) seaice variability. Finally, it was also found that the persistence of seaice anomalies in North Pacific basically is six months, while that in North At lantic is up to one year.