Labour market segmentation in developing countries has been considered in a growing literature, some of which suggests an informal sector wage premium. However, such studies have mainly focused on urban labour markets and have not discriminated between the informally self-employed and wage workers. This paper examines segmentation in rural markets for agricultural wage workers in Ethiopia, controlling for location, farming systems and observed worker characteristics. Applying an endogenous switching model with simultaneous estimation of wage equations it establishes an informal sector wage premium, self-selection into the informal sector and sectorally-distinct wage determination mechanisms.