In this article, I investigate a hypothesis concerning the supposed influence of Spinoza on Marx’s works. Setting out from a comment made by Althusser – ‘[Spinoza] is the only direct ancestor of Marx’ – I try to demonstrate that even though the relationship between Spinoza and Marx has limited support at a historiographical level, a determined set of ideas of Spinoza can be connected to some of Marx’s political objectives in the period prior to 1845. This argument is supported through Marx’s notebooks devoted to studying Spinoza’s Theological-Political Treatise, written in 1841, and his refutation of Spinoza in The Holy Family. However, contrary to what could be expected, when Marx abandoned his most pronounced idealistic phase, within which Spinoza played a certain role, he rebelled against Spinozism at the same time. Nonetheless, it is one thing to repudiate Spinoza’s name, and a very different thing to repudiate Spinoza’s ideas.