This paper investigates the effect of engaging students in designing interactive multimedia programs. The design process has been shown to heighten motivation and to develop skills in project management, research, organization and representation, presentation, and reflection. At the same time, previous studies have also revealed that it is necessary for teachers to implement and sustain learner-as-designer environments by thoroughly explaining design knowledge and design issues. The semester-long study lasting approximately 18 weeks described in this report implemented such an environment with a four-phase model in which students: (1) received explicit instruction about the design process; (2) took part in a simulated production environment; (3) interacted directly with clients of the programs; and (4) interacted directly with multimedia experts, some of whom were guest speakers and some of whom coached the students throughout the semester. The treatment class consisted of 24 high school students from grades 10 through 12 of whom 71% were minority students and 16% were considered learning disabled. Students were divided into four teams, three of which opted to assemble multimedia presentations on separate topics for the local children's museum, and one of which decided to develop a CD-ROM yearbook. Students were asked to complete questionnaires, to list and prioritize design tasks, and to submit to observations and interviews. Their comments, along with statistical data, shed light on the value of various collaborative activities and about their growing sense of technical competence and self-efficacy. (Contains 18 references and 7 tables.) (BEW)