This paper empirically explores the relations between alternative organizational designs and a firm's ability to explore as well as exploit. We operationalize exploitation and exploration in terms of innovation streams; incremental innovation in existing products as well as exploring into architectural and/or discontinuous innovation. Based on in-depth, longitudinal data on 13 business units and 22 innovations, we investigate the consequences of organization design choices on innovation outcomes as well as the ongoing performance of existing products. We find that ambidextrous organization designs are significantly more effective in executing innovation streams than functional, cross-functional, and spinout designs.