Small-scale credit provided under appropriate conditions has long been recognized as an engine of rural development, and informal institutions have played an important role in providing this. However, their capacity is limited, but formal institutions with much greater financial capacity rarely reach rural people because of the risks and transaction costs. Describing how in Ghana the two types of institution have worked together, to their mutual advantage and to that of small-scale rural traders and borrowers, this paper draws out the preconditions that must be in place for linkages of this kind to prosper elsewhere.