This paper uses a large sample of South Korean union members working in different industries and occupations to test a model of union satisfaction. The results suggest that union-member relations- member representation and union leader effectiveness — are more important than the economic results that unions provide to members. These findings are in line with our general argument that, where unions rely on decentralized collective bargaining as the prime method of employment regulation, they depend heavily on internal union relations for their effectiveness. We contend that, if unions are to limit the decline in their influence, assessing and changing internal union relations should be a priority.