Placement is considered one of the most arduous and time-consuming processes in physical implementation flows for reconfigurable architectures, while it highly affects the quality of derived application implementation as it is tightly firmed to the total wirelength and hence the maximum operating frequency. This problem becomes more acute for three-dimensional (3-D) architectures since the complexity of such architectures imposes additional challenges that have to be sufficiently addressed. Throughout this paper we introduce a novel placement algorithm, targeting 3-D reconfigurable architectures, based on Ant Colony Optimization (ACO). Experimental results validate the effectiveness of our algorithm since it achieves 10% reduction in the critical path delay on average. Additionally, in contrast to relevant approaches which are executed sequentially, the proposed algorithm exhibits inherent parallelism and can take full advantage of today's multi-core architectures.