Abstract: Side scan sonar is one of the most widely used imaging systems in the underwater environment. It is relatively cheap and easy to deploy, in comparison with more powerful sensors. Although side scan sonar does not provide seafloor bathymetry directly, its records are directly related to seafloor images. In the paper, the method for 3D seafloor relief reconstruction from side scan sonar data is presented. The method is based on the Shape From Shading technique and for estimation of a bottom depth at a currently processed point, it uses the information from both currently processed and previous ping. The results obtained by several versions of the developed algorithm are presented. The obtained results are promising and also show how the performance of the proposed algorithm might be improved in further work.