Malaria rapid diagnostic tests (MRDTs) have the potential of significantly improving the diagnosis of malaria in developing countries, especially where microscopic diagnosis is not available. However, in order for them to be effective, the informational inserts and product design must be clearly understood by the health workers in rural developing country facilities. This report summarizes a study in Malawi that led to the improvement of two different MRDTs. Using quality design principles, a research team, composed of technical experts and local researchers and sponsored by the Quality Assurance Project, developed and tested a user-friendly job aid that dramatically improved health workers' ability to use the tests properly without training. The team was able to recommend to the manufacturers some modifications to the kit design and packaging that would increase the likelihood that the kit would be used correctly every time.