Geometry optimization of carbon dioxide clusters (CO2)(n) with the size of 4 <= n <= 40 is performed by a heuristic and unbiased method combined with geometrical perturbations. Comparison with the global minima reported in the literature shows that the present method reproduces the global minima for clusters with n = 6, 8, 13, 19, 28, 30, and 32 and yields new global minima for (CO2)(23), (CO2)(25), and (CO2)(35). For the other clusters under investigation, global minima are first reported in this article. Structural features of CO2 clusters and efficiency of the optimization method are discussed.