This study employed problem-based learning (PBL) for project work in a Year 9 biology class. The purpose of the study was to investigate (a) how self-generated problems and questions directed students in their learning, (b) how students reacted to this instructional approach, and (c) the problems that they encountered. Students formulated problems that they were interested in investigating and posed questions to which they wanted answers. These became the focus of subsequent inquiry and served to direct student learning in collaborative groups. Data sources included observation and field notes, students' written documents, audiotapes and videotapes of students working in groups, and student interviews. Issues relating to the design, management, and implementation of PBL in project work are discussed. (Contains 4 tables.)