In Ireland, credit unions appeal to a broad socio-economic spectrum and have become integrated into the mainstream financial services market. As many credit unions seek to provide services comparable to conventional banking institutions, they risk eroding their distinctive co-operative ethos. A key differentiating characteristic of credit unions is concern for community and social responsibility. In a business climate where many consumers question the societal and/or environmental impact of businesses, credit unions enjoy a distinct competitive advantage. Despite this, the role of credit unions in promoting societal wellbeing has received limited attention in academic literature. In order to capitalise on its unique competitive advantage, and fulfil its objective of social responsibility, the credit union movement must develop approaches to optimising and assessing how it impacts on communities. Based on research conducted in 40 credit unions, this paper explores the key benefits accruing to communities through intentional and incidental societal impacts. It offers some suggestions for the range of instruments that credit unions can use to optimise the principle of social responsibility. It argues that the impact of credit unions on their communities cannot be left to chance but requires management through the identification and definition of social goals and through periodic assessment of the credit union's success in meeting its targets