The informal economy in Cambodia faces many challenges to establishing universal health insurance, including the high cost of private medical aid products and lack of access to social security. Currently, the Cambodian government is discussing the implementation of a National Medical Benefit Fund (NMBF) as part of the 1993 Social Security Act to cover both informal workers and the unemployed. However, establishing such a fund raises questions about its potential characteristics and challenges, like the affordability of coverage for informal workers in Cambodia. This analysis examines Cambodia's health system and informal economy to understand the opportunities and difficulties of implementing an NMBF.