Computer and video games for children have gained negative publicity due to reported associations between intensive gaming and aggressive behaviour, school failure, and overweight. While most studies centre upon negative consequences of video games, their innovative potentials tend to be overlooked. One field for the innovative use of computer games is child psychotherapy. By including therapeutic concepts into a video game, children can be offered attractive electronic homework assignments that enable them to rehearse and repeat basic psychoeducational concepts they have learned during therapy sessions. Moreover, therapeutic games can help therapists to structure therapy sessions. Psychotherapeutic computer games translated into foreign languages could form a useful tool in the treatment of migrant children. 'Treasure Hunt' is the first serious game based on principles of cognitive behaviour modification. It is developed for eight to twelve year old children who are in cognitive-behavioural treatment for various disorders. Reactions of children and therapists to experimental versions of the game are positive. Serious games might prove a useful tool to support psychotherapeutic treatment of children.