Competition between microfinance institutions (MFIs) in developing countries has increased dramatically in the last decade. We model the behavior of non-profit lenders, and show that their non-standard, client-maximizing objectives cause them to cross-subsidize within their pool of borrowers. Thus when competition eliminates rents on profitable borrowers, it is likely to yield a new equilibrium in which poor borrowers are worse off. As competition exacerbates asymmetric information problems over borrower indebtedness, the most impatient borrowers begin to obtain multiple loans, creating a negative externality that leads to less favorable equilibrium loan contracts for all borrowers. (c) 2005 Elsevier B.V All rights reserved.