The informal food sector is a vital part of rural, peri-urban and urban communities sitting alongside formal economic activities and trading procedures for centuries. It largely contributes to the local economy. However, since they source their supplies from agricultural produce in the local markets, they become vulnerable to the uncertainties which could possibly result to livelihood vulnerability. This descriptive study aimed to assess and describe the livelihood vulnerability level of the informal food sector, determine the issues, challenges and opportunities and identify policy implications that could improve the livelihood resiliency of the informal food sector in Occidental Mindoro. The Livelihood Vulnerability framework of Hahn (2009) where seven indicators were used in determining the vulnerability: socio-demographic profile, livelihood strategies, social network, health security, food security, access to utilities, and disaster experience. A random sampling of 200 informal food enterprises was employed to three market areas San Jose, Magsaysay and Rizal in Occidental Mindoro. The livelihood vulnerability index was used to describe the vulnerability level. The study revealed a low to moderate vulnerability level of the informal food enterprises. The issues, challenges and opportunities of the informal food sector include their limited access to formal credits, high dependency ratio, poor educational background, low marketing skills all contribute to their livelihood vulnerability. However their high adaptive capacity specifically in livelihood diversification and their ability to supply the essential needs of the market enhance their resilience They bank on two business strengths: affordability and availability which have become their investment to develop their regular buyers.