Surface-ocean changes in the North Atlantic are closely linked to modes of atmospheric variability, the most dominant of which is the North Atlantic Oscillation. The aims of this study were to investigate high-frequency climate variability in the North Atlantic through the use of high-resolution fossil marine diatom records spanning the last 2000 years. Core sites in the Muros Ria, in northwest Spain, and on the western Norwegian Margin were selected for their high sedimentation rates and their proximity to the NAO pressure centres. 'he diatom record's high resolution permitted comparison to nearby instrumental time series where significant relationships were found with precipitation, the NAO Index and extended NAO Index reconstructions.