In many design applications, designers often have to find the best geometrical configurations so as to achieve certain objectives with the minimum amount of materials used. Such shape or topology optimization problems are usually much harder to solve than nonlinear optimization problems in a fixed domain. In this paper, we use the recently developed bat algorithm to solve topology optimization problems. Results show that the distribution of different topological characteristics such as materials can be achieved efficiently. We have also tested the bat algorithm by solving nonlinear design benchmarks. Results suggest that bat algorithm is very efficient for solving nonlinear global optimization problems as well as topology optimization.