Anti-semitism in the Dutch labour movement has not been studied sufficiently. This is certainly true with regard to Ferdinand Domela Nieuwenhuis and the early socialist movement in the nineteenth century. However, we have to take anti-Jewish propaganda into account in order to understand why the Jewish proletariat joined the socialist ranks at such a late stage, only after the reformist wing split form Domela's Social Democratic League (SDB) into the Social Democratic Labour Party (SDAP) in 1894. This article aims to address this lacuna, and demonstrates that Domela has been using Anti-semitic stereotyping against the parliamentary-orientated reformists, because his main rival P.J. Troelstra was dependent on a modest group of Jewish diamond labourers in Amsterdam. Once the conflict was over Anti-Semitism faded into the background again.