The eddy-induced diffusivity for heat at the surface of the western North Atlantic Ocean is estimated using satellite altimetry and sea surface temperature data. A rotational eddy flux is removed from the total eddy flux following the ideas of Marshall and Shutts (1981). The resulting eddy-induced diffusivity shows considerable spatial variability with a value near 104 m2 s-1 just to the south of the Gulf Stream and values in the range 1--2 ¿ 103 m2 s-1 within the Gulf Stream itself.