A medical image output system includes: a medical image transferring apparatus and plural medical image forming apparatus. Each medical image forming apparatus includes a storage unit for storing image formable region information. The transferring apparatus includes: an obtaining unit for obtaining the stored image formable region information; a determination unit for determining an image formation size based on the obtained image formable region information; a unit for expanding or contracting the received medical image data according to the determined image formation size; and a transfer unit for transferring the expanded or contracted image data to the medical image forming apparatus.