According to a game system and a storage medium having stored therein a game program of the present invention, among a plurality of game machines communicably connected to each other, a game machine 10a acting as a card reader machine reads card data and sends the card data to a game machine 10b. Game machines 10b to 10d compete against each other in a game and the card data is sent only to a specific game machine(s) 10 based on game results. That is, an amusing game is provided which uses card data to be sent as special prize data which is given only to a specific player(s).