Heat flow studies were conducted in January-February 1987, off the Atlantic Coast the R/V Akademik Nikolai Strakhov. Two areas were surveyed, one transecting the Salt Dome Province and the Campeche Canyon, in the Gulf of Mexico, and the other on the eastern flank of the Yucantan Peninsula. Conductive heat flow through the bottom sediments was determined as the product of vertical temperature gradient and in situ thermal conductivity, measured with a thermal probe using a multithermistor arry and real-time processing capabilities. Forward two-dimensional modeling allows us to estimate heat flow variations at both sites from local disturbances and to obtain average heat flow vlaues of 51 mW/m2 for the transect within the Gulf of Mexico and 38 and 69 mW/m2 for two basins within the Yucatan area. Sea bottom relief has a predominant effect over other environmental factors in the scatter of heat flow determination in the Gulf of Mexico. ¿ American Geophysical Union 1990