Concentrated photovoltaics (CPV) has recently gained popularity due to its ability to deliver significantly more power at relatively lower absorber material costs. In CPVs, lenses and mirrors are used to concentrate illumination over a small solar cell, thereby increasing the incident light by several folds. This leads to non-uniform illumination and temperature distribution on the front side of the cell, which reduces performance. A way to limit this reduction is to optimize the metallization design of the solar cell for certain non-uniform illumination and temperature profiles. Most of the existing metallization optimization methods are restricted to the conventional H-pattern, which limits the achievable improvements. Topology optimization alleviates such restrictions and is capable of generating complex metallization patterns, which cannot be captured by the traditional optimization methods. In this paper, the application of topology optimization is explored for concentrated illumination conditions. A finite element model that includes all relevant resistances combined with topology optimization method is presented and the applicability is demonstrated on non-uniform illumination and temperature profiles. The finite element model allows accurate modeling of the current density and voltage distributions. Metallization designs obtained by topology optimization significantly improve the power output of concentrating solar cells.