Observations of sea ice mass balance and temperature made during the year-long Surface HEat Budget of the Arctic Ocean (SHEBA) field experiment were used to calculate monthly estimates of the ocean heat flux for a variety of ice types. The ocean heat flux displayed a strong seasonal cycle, with values of a few W m-2 from October through June followed by a steady increase in June and July. By the end of July the the ocean heat flux for undeformed ice reached a peak value of about 33 W m-2 during a period of substantial ice motion. The annual average ocean heat flux for multiyear ice ranged from 7.5 W m-2 for undeformed ice to 10.4 W m-2 for a melt pond to 12.4 W m-2 for an old ridge. Annual averages measured at SHEBA were more than twice as large as values observed in 1975 during AIDJEX.