A communication game system includes a plurality of game apparatuses which are able to wirelessly communicate with each other. Each of the game apparatus registers identifying information of an opponent obtained by a short-distance wireless communication or by user's manual input in a friend list. Thereafter, the game apparatus connects to the Internet, and inquires whether it is possible to communicate with an opponent in the friend list over the network. If it is possible to communicate, the game apparatus obtains an address of the opponent to make a network communication. Even if a user makes a short distance wireless communication with a friend to exchange and register the identifying information or registers the friend by hand and then is parted from the friend, the user can safely communicate with the friend across the network without being exposed to unknown players. In a case that an additional opponent is to be added to the multiplayer game session, one of the participants transmits identifying information to introduce the communicating opponents to each other. The game apparatuses introduced to each other make a communication over a network, and add the identifying information of the opponents to the friend list, if necessary.