Operational/implementation research (OR/IR) is a key activity to improve disease control programme performance. We assessed the extent to which malaria and tuberculosis (TB) grants from the Global Fund to Fight AIDS, Tuberculosis and Malaria («Global Fund») include support for OR/IR, and discuss the implications of the current Global Fund operating mechanisms for OR/IR support.; The situation analysis focussed on malaria and TB, while HIV was excluded. Stakeholder interviews were conducted at the Global Fund secretariat and in six purposefully selected high disease burden countries, namely the Democratic Republic of the Congo, Ethiopia, India, Indonesia, Myanmar and Zimbabwe. Interviewed in-country stakeholders included the relevant disease control programme managers, project implementation partners, representatives from international organisations with a stake in global health, academic and governmental research institutions, and other relevant individuals such as members of the country coordination mechanism. Additionally, documentation of grants and OR/IR obtained from the Global Fund was reviewed.; The Global Fund provides substantial resources for malaria and TB surveys, and supports OR/IR if such support is requested and the application is well justified. We observed considerable variations from one country to another and between programmes with regards to need, demand, absorption capacity and funding for OR/IR related to malaria and TB. Important determinants for the extent of such funding are the involvement of national research coordination bodies, established research agendas and priorities, human and technical research capacity, and involvement of relevant stakeholders in concept note development. Efforts to disseminate OR/IR findings were generally weak, and the Global Fund does not maintain a central OR/IR database. When faced with a need to choose between procurement of commodities for disease control and supporting research, countries tend to seek research funding from other donors. The Global Fund is expected to issue more specific guidance on the conditions under which it supports OR/IR, and to adapt administrative procedures to facilitate research.; The importance of OR/IR for optimising disease control programmes is generally accepted but countries vary in their capacity to demand and implement studies. Countries expect guidance on OR/IR from the Global Fund. Administrative procedures specifically related to the budget planning should be modified to facilitate ad-hoc OR/IR funding. More generally, several countries expressed a need to strengthen capacity for planning, negotiating and implementing research.