In malaria-endemic countries, people commonly assume they have malaria when sick and treat themselves accordingly. The Affordable Medicines Facility-malaria (AMFm) will make effective drugs more available everywhere. If longstanding problems can be successfully addressed, the use of microscopy and rapid diagnostic tests (RDTs) for malaria diagnosis alongside AMFm (though not necessarily directly part of it) could improve the management of both malaria and other febrile illness, as well as the cost-effectiveness of AMFm. In peripheral areas, RDTs are the only practical option, but available RDTs have limitations: all-or-none test results, variable heat stability, an inability to diagnose non-falciparum malaria and safety risks (especially HIV and hepatitis B) related to blood sampling. Of equal concern is that negative test results—meaning no malaria—are often ignored and patients treated anyway. R&D to solve technical problems and operational research on better ways to deploy RDTs and to make diagnosis count are needed.