The autonomous underwater vehicle (AUV) DAURADE platform can acquire bathymetry with two acoustic sensors: a multibeam echo sounder (MBES) and an interferometric sidescan sonar (ISSS). The two sensors (MBES and ISSS) are synchronized and they can simultaneously operate and acquire the bathymetry with different resolutions, geometries and error models. This complementarily allows us to improve the accuracy and the coverage of the collected bathymetric data by fusing both of them. We applied the fusion process on actual data from the two bathymetric sensors of DAURADE (Reson 7125 MBES and Klein 5000 Interferometric); the obtained results are presented and discussed.