A research partnership of representatives from labor, academia, and public health enabled unionized San Francisco hotel workers to achieve important policy changes in workplace health and safety. Known as the "Housekeeping Study," the project took sixteen months to complete. A unique aspect of the project was that it utilized participatory action research methods, involving workers themselves as full participants in the study. A core group of 25 hotel room cleaners was involved in each phase of the project. The study developed health data which enabled room cleaners and their union to formulate and justify a contract proposal calling for a significant reduction in housekeeping workloads. The employer association agreed to a contract which reduced the maximum required room assignment from 15 rooms to 14 rooms per day in 14 San Francisco hotels. By lowering the maximum work assignment, these workers set a new standard which can potentially protect the health of room cleaners across the country. The project can serve as a model for worker and union participation in academic research, as well as for the application of research to improving working conditions, particularly for low-wage immigrant workers.