We present 99 new heat flow determinations obtained with a regular sampling (2--3 km) along two seismic profiles across the Mascarene Ridge, Indian Ocean. This aseismic ridge is volcanic relief due to the activity of a hot spot, now responsible of the active volcanism of Reunion Island. Our sampling technique allows us to identify short-wavelength processes such as slope-driven water flows that affect heat flow on the ridge. With the exception of these perturbed sites, heat flow appears to be very uniform across the ridge and significantly higher (6--8 mW m-2) than the reference heat flow predicted for the seafloor age. Although this anomaly is low, it confirms other evidence for thermal rejuvenation of the lithosphere based on gravity and bathymetry. The set of information now available for the Mascarene Ridge seems to indicate a mixed mode of compensation with dynamical support below the front of the swell track and thermal support behind for the order part of the swell.¿ 1997 American Geophysical Union