According to WHO, while 50 percent of global health research and development (R&D) in 1992 was undertaken by private industry, less than 5 percent of that was spent on diseases specific to less developed countries (LDCs).1,2 Despite this, private industry has produced major drug discoveries and developments for serious LDC disease threats, including malaria, TB, hepatitis B, river blindness, meningitis, leprosy, sleeping sickness and trachoma. Moreover, the development of globally–applicable drugs and vaccines has led to important advances in public health in developing countries. At the same time, the simple fact is that every company in the biopharmaceutical industry has a limited number of research and development programmes in their portfolio. These projects are regularly reviewed against each other using a variety of analytical tools. Fundamentally the process tends to favour those projects with a higher probability of success and which, if successful, would serve markets with a larger value. As a result, there is underinvestment in and comparative neglect of some diseases concentrated in LDCs, such as tuberculosis and malaria, despite their high global disease burden. It is therefore generally agreed that new mechanisms and incentives are needed to encourage industrial R&D in such diseases. In this paper, we summarize some recent thinking about ways to stimulate industrial R&D for neglected infectious diseases, and we argue that enlarging the value of the market for drugs and vaccines for these diseases is a critical step toward stimulating R&D.