The political and organisational routes opened up on the contemporary left following the financial crisis have seen a revival of class composition analysis as a means of comprehending a broad array of social and economic phenomena both within and beyond the workplace. Contextualising contemporary class composition analysis as a long-standing component of autonomist Marxism, this article argues that its application amid the left’s electoral turn exposes to scrutiny deeper-running weaknesses. The article first presents a history of class composition analysis through operaismo into postoperaismo. The second part of the article discusses four interconnected new directions in class composition analysis: Hardt and Negri’s Assembly; the analysis of social composition offered by the Notes from Below collective; Keir Milburn’s analysis of ‘generation left’; and, finally, the uptake of some of these ideas among commentators on the left of the British Labour Party like Paul Mason. The article then discusses the theoretical and strategic implications of these contributions through the prism of critiques of class composition analysis put forward by other theorists in the autonomist Marxist tradition. Noting the possible limitations confronting the application of class composition analysis to contemporary challenges faced by the post-crisis left, the penultimate section considers Labour Process Theory as a theoretical alternative implicit in recent critiques of contemporary class composition analysis, arguing that while Labour Process Theory’s analysis of the ‘politics of production’ captures the contingency of the connection between the workplace and formal politics, it leaves unresolved the lack of a distinctive theory of the latter on the contemporary left. The final section reconnects the discussion to the legacy of operaismo by exploring Mario Tronti’s recently translated work on the ‘autonomy of the political’ as a more substantial articulation of the specificity of politics against the backdrop of class conflict at the point of production. The conclusion relates this back to recent strategic issues in the Labour Party and broader labour movement.