The Cenozoic evolution of the Arctic Ocean is closely related to two tectonic events: the rifting of the Lomonosov Ridge from the Siberian Shelf, and the opening of the Fram Strait. The duration of the rift phase between the Lomonosov Ridge and the shelf is poorly constrained by marine data, and is difficult to describe. The drift of the rigde, however, is well documented by seafloor spreading anomalies in the Amundsen and Nansen basins. During most of the basin formation the spreading was ultra slow, as indicated by magnetic and seismic data. The only scientific deep drill hole in the central Arctic is located on the ridge. Analyses showed that the environment between 55 and 45 Ma was completely different to what we observe today. E.g., surface water temperatures were well above 20°C in the summer. Unfortunately, the drilling information is not complete in describing the transition from the warm Arctic to the present day situation.Thus, the role of the Fram Strait opening some 15 Ma between North Greenland and Svalbard is speculative. Coring information indicates that around 17 Ma the Arctic Ocean became ventilated, which can be related to the final formation of a deep water connection in the Fram Strait. Geophysical data furthermore indicate that most likely before that tectonic event shallow water connections existed in the Fram Strait to allow limited water exchange e.g. across the Yermak Plateau. In order to address these problems continued broad research activities are necessary including deep drilling during the next decade.