A dual bin combine system for combine harvesters which increases the storage capacity of harvested grain products when compared with previous systems. The dual bin combine system generally includes a combine harvester having a frame and a first tank for storing material harvested by the combine harvester. A frame extension, which extends in a rearward direction from the frame, includes a second tank. A transferring conduit extends from the first tank to the second tank. When operating the harvester, material may be fed from both tanks to reduce downtime unloading and thus more efficiently harvest crops.