Background This is the fourth of our 11-paper supplement on “Community Health Workers at the Dawn of New Era”. Here, we first make the case for investing in health programmes, second for investing in human resources for health, third for investing in primary healthcare (PHC) workers, and finally for investing in community health workers (CHWs). Methods Searches of peer-reviewed journals and the grey literature were conducted with a focus on community health programme financing. The literature search was supplemented with a search of the grey literature for information about national health sector plans, community health strategies/policies, and costing information from databases of various countries’ ministries of health, and finally a request for information from in-country partners. Results The global shortage of human resources for health is projected to rise to 18 million health workers by 2030, with more acute shortages in Africa and South Asia. CHWs have an important role to play in mitigating this shortage because of their effectiveness (when properly trained and supported) and the feasibility of their deployment. Data are limited on the costs of current CHW programmes and how they compare to government and donor expenditures for PHC and for health services more broadly. However, available data from 10 countries in Africa indicate that the median per capita cost of CHW programmes is US$ 4.77 per year and US$ 2574 per CHW, and the median monthly salary of CHWs in these same countries is US$ 35 per month. For a subset of these countries for which spending for PHC is available, governments and donors spend 7.7 times more on PHC than on CHW programming, and 15.4 times more on all health expenditures. Even though donor funding for CHW programmes is a tiny portion of health-related donor support, most countries rely on donor support for financing their CHW programmes. Conclusion The financing of national CHW programmes has been a critical element that has not received sufficient emphasis in the academic literature on CHW programmes. Increasing domestic government funding for CHW programmes is a priority. In order to ensure growth in funding for CHW programmes, it will be important to measure CHW programme expenditures and their relationship to expenditures for PHC and for all health-related expenditures.