This study is based on a nationwide survey of local Muslim congregations (n  =  105) and focuses on the patterns and function of voluntary social work carried out by the congregations. Muslim congregations in Sweden are not only religious meeting places, but also social meeting places and centres for the organisation of a broad range of social welfare services: outreach activities, support to newly arrived immigrants and activities for children and young people. The work is carried out on a voluntary basis at the intersection between the congregation and the community. Muslim voluntary social work appears to be most intensive in smaller municipalities with a large amount of unemployment. The dominant discourse on Islam in Europe has claimed that Muslim social work is part of an attempt to create self-sufficient enclaves that impede the integration of Muslim immigrants into the wider society. Claims of this type seem, however, to be largely unfounded. The Swedish Muslim congregations that carry out the most voluntary social work are those most interested in co-operation with other organisations and with authorities of different types and those that have the most positive experiences of the wider society.