In recent years, development assistance for health (DAH) from Organization of Economic Cooperation and Development countries has dramatically increased. It is then natural to ask what has been the impact of this assistance. As with other types of developmental assistance from richer countries, studies have shown that the effectiveness of DAH measured in terms of outcome is ambiguous. An important factor that affects aid effectiveness is the various modalities through which aid is given. Analyses of these modalities show that much can be improved and the pathways and the associated incentive structures through which DAH can impact health needs to be examined.