A dual-purpose dumbbell has a bar, two weights and two adjusting assemblies. The bar has two ends. The two weights are mounted rotatably respectively on the ends of the bar and can be configured longitudinally or transversely relative to the bar. The adjusting assemblies are mounted respectively between the ends of the bar and the weights to allow the weights rotated relative to the bar. When the weights are configured longitudinally, the dual-purpose dumbbell is used as a dumbbell or a weighted baton. When the weights of the dual-purpose dumbbell are configured transversely, the dual-purpose dumbbell can be used as a handle for doing pushups. Since the dual-purpose dumbbell can be used as a dumbbell, a weighted baton and a handle for use when doing pushups, less space is required to store exercise equipment and less cost is incurred to procure the exercise equipment.