Several data-centric communication paradigms have been proposed in the domain of wireless sensor networks (WSN). Therefore, the principles of operation and maintenance in such networks are changing in order to control massively distributed systems. Previous addressing schemes fail or produce too much overhead even if only locally unique addresses of sensor nodes are required. In this paper, we present a dynamic address allocation scheme for localized address assignments in WSN. We developed a round-based address assignment with subsequent duplicate address detection that operates in a self-organized manner. It inherently allows busy-sleep periods and does not assumes always awake nodes. In order to verify the approach, we implemented the algorithm on Mica2 sensor motes and tested it in a WSN maintenance scenario. The results demonstrate that our method works well for operation and maintenance of WSN without prior address assignments.