A chip-on-film package includes a base film having a top surface and a bottom surface, and a circuit region; a source driver chip and a gate driver chip mounted on the circuit region; a first conductive line on the top surface of the base film, a second conductive line on the bottom surface of the base film, and a conductive via that connects the first and second conductive lines to each other; a first row of bonding pads on the circuit region and connected to the source driver chip; a second row of bonding pads on the circuit region and connected to the source driver chip and the gate driver chip; and a test pad outside the circuit region and connected to the first and second conductive lines and the conductive via.