ACCION International has developed relationships with several commercial banks to launch and expand microfinance operations through an approach known as the service company model. This paper describes how the service company model addresses the key issues in commercial bank entry into microfinance, identifies success factors for establishing a well-functioning microfinance services company, and presents results and lessons from the two microfinance service companies with the longest experience, SOGEBANK/SOGESOL in Haiti and Banco del Pichincha/CREDIFE in Ecuador.