The new 3D bathymetry model for the largest known subglacial lake in Antarctica – Lake Vostok – was developed via inversion of airborne gravity data, constrained by 60 seismic soundings. The presented model consists of water and unconsolidated sediment layers overlying the host rock, with densities of 2.55 g/cc for host rock and 1.85 g/cc for sediment. The sediment layer was originally interpreted from seismic data as 50 m thick in the northern part of the lake, while revised seismic interpretations suggest that this layer is 350 -380 m thick. The revised thickness makes the unconsolidated sediments in Lake Vostok a significant gravity anomaly (up to 8 mGal in the northern basin). Previous gravity models (based on the same gravity dataset) are compared and contrasted with our new one. Our presented 3D bathymetry model of Lake Vostok corresponds better with seismic data (RMS of 125 m) than two previous models.