Teenagers with diabetes often experience their disease as a heavy burden, feeling estranged from their peers. Traditional aids to monitoring and controlling the illness are often not used by this group, because they seem to enhance this feeling. Preliminary interviews with a focus group indicate that teenagers will be motivated by competing to maintain a certain level of blood glucose, regular measurements and assessment of the glucose level in their diet as well as insulin dosing at mealtimes. By the use of serious gaming and taking a user oriented approach for the development process, the DiaApp project will develop a smartphone app that will incorporate disease monitoring and maintenance into a game, thus encouraging the teenagers to manage their disease better and educating them about it as well.