This paper describes a project to explore issues surrounding the development of a collaborative handheld educational application for children. A user-centered, iterative design process was used to develop GeneyTM , a collaborative problem solving application to help children explore genetic concepts using PalmTM handheld computers. The design methodology utilized mock-ups of representative tasks and scenarios, pre-design meetings with target users, prototype development, and feedback sessions with target users. The results of this work identify an effective way of utilizing handheld computers for collaborative learning and provide important insights into the design of handheld applications for children. This work also illustrates the necessity of user-centered design when new user groups are targeted, especially when novel user interface paradigms are employed that go beyond current windows-based interfaces. Keywords CSCL, CSCW, handheld computing, PDAs, children, education, user-cent...