In a recent article in Sociology, Mouzelis argues that Lockwood’s distinction between system integration and social integration is, with some modifications, still to be retained because of its logical coherence and its methodological virtues . While its basic value is recognised, this article reconsiders the distinction in the light of some recent achievements in social theory. It is argued that the distinction does not merely offer two different perspectives on society but that, in the actual social world, both dimensions are intertwined in a number of ways. In particular, reflexive actors can draw the distinction themselves which raises questions about the objective status of ‘incompatibilities’. The implications are developed through some reflections on the nature of social processes as well as the role of institutions, strategic action and conflicts. On the one hand, it is shown that system integration is an important objective for social agency, since many actions are aimed at controlling the performance of processes. On the other, social integration has a decisive impact on those processes because conflict and co-operation transform the institutional preconditions those processes are based upon. The social–system integration distinction offers therefore interesting insights into how social actors themselves attempt to cope with their worlds. Apart from being a methodological tool, the distinction expresses a substantial characteristic of society.