The mean seasonal cycles of six state-of-the-art surface heat flux products (three based on widely available data and three based on numerical model reanalysis fields) are compared in the equatorial Pacific with heat fluxes computed from Tropical Atmosphere-Ocean (TAO) buoy data. Net surface heat flux and individual flux components derived from these products exhibit large deviations from TAO. We find that a significant contribution to these differences, which are often 50 W m-2 or more for net flux, is the use of systematically biased bulk variables in the computation of turbulent surface heat fluxes. We also find that for some products, compensating errors in bulk variables lead to fortuitous agreement with turbulent heat fluxes estimated from TAO. Finally, comparisons of TAO-derived fluxes with tuned and untuned heat flux estimates from the Comprehensive Ocean Atmosphere Data Set indicate better agreement with untuned fluxes, suggesting that commonly used ad hoc strategies to close the global ocean heat budget are not strictly valid. ¿ 2001 American Geophysical Union