Abstract. An interior point method for the structural topology optimization is proposed. The linear systems arising in the method are solved by the conjugate gradient method preconditioned by geometric multigrid. The resulting method is then compared with the so-called optimality condition method, an established technique in topology optimization. This method is also equipped with the multigrid preconditioned conjugate gradient algorithm. We conclude that, for large scale problems, the interior point method with an inexact iterative linear solver is superior to any other variant studied in the paper.Keywords:. topology optimization, multigrid methods, interior point methods, preconditioners for iterative methods MSC2010:. 65N55, 35Q93, 90C51, 65F081. Introduction. The discipline of topology optimization offers challenging problems to researchers working in large scale numerical optimization. The results are essentially colors of pixels in a 2d or 3d "pictures". Hence, in order to obtain highquality results, i.e., fine pictures capturing all details, a very large number of variables is essential. In this article we only consider the discretized, finite dimensional topology optimization problem. For its derivation and for general introduction to topology optimization, see, e.g., [5].We will consider the basic problem of topology optimization: minimization of compliance under equilibrium equation constraints and the most basic linear constraints on the design variables: