This study focuses on micro and small enterprises (MSEs) in five low income countries located in Sub-Saharan Africa and investigates the various firm attributes that determine access to credit, in particular the role of firm informality. The topic has become a central focus of MSE rejuvenation efforts around the world, and most economies are encouraging their MSEs to be formal to enhance their credit accessibility. This study uses World Bank Informal and formal Enterprise Surveys to collect data. Informality may be endogenous to credit constraints in several ways, which creates econometric problems when empirically modelling access to credit. Using an instrumental variable approach, the results show that the higher the probability of a firm operating in the formal sector, the greater its access to external credit. The importance of formalisation polices to reduce the informality of the MSE sector is discussed in the context of the research findings.