Core NWR 5 from Northwind Ridge in the western Arctic Ocean contains a climatic record that extends back for over 1 million years. Dark brown beds with abundant planktonic foraminifers represent interglacial conditions, whereas glacial and transitional conditions are represented by lithologies barren or nearly barren of planktonic foraminifers. We conclude that seven, and possibly all nine, interglacials of the Brunhes magnetic chronozone (the last 780,000 years) are represented in NWR 5. For about the last 800,000 years, the western Arctic Ocean apparently had a permanent, thick ice cover and was unable to support significant populations of planktonic foraminifers except during major interglacials when seasonally open and high-productivity surface waters occurred at least along the basin margins. Our results support previous interpretations that climate variations in the Arctic are in phase with glacial/interglacial cycles observed in other proxy records of the Brunhes.