As wind turbines continue to grow in size, it becomes increasingly important to ensure that they are as structurally efficient as possible to ensure that wind energy can be a cost-effective source of power generation. A way to achieve this is through weight reductions in the blades of the wind turbine. In this study, topology optimization is used to find alternative structural configurations for a 45 m blade from a 3 MW wind turbine. The result of the topology optimization is a layout that varies along the blade length, transitioning from a structure with trailing edge reinforcement to one with offset spar caps. Sizing optimization was then performed on a section with the trailing edge reinforcement and was shown to offer potential weight savings of 13.8% when compared with a more conventional design. These findings indicate that the conventional structural layout of a wind turbine blade is sub-optimal under the static load conditions that were applied, suggesting an opportunity to reduce blade weight and cost. Copyright © 2012 John Wiley & Sons, Ltd.