Relational Egalitarianism focuses on the construction of equal social relationships between persons. It strongly opposes luck egalitarianism, which understands equality as a distributive ideal. In Cohen’s theory of justice, luck egalitarianism and relational egalitarianism simultaneously exist, and Cohen provides arguments corresponding to each. In this paper, we explore the manifestation of tension between these two forms of egalitarianism in his theory. In addition, we also reconstruct some possible solutions provided by Cohen to soften this tension, including the three approaches of market mechanism, egalitarian ethos and value pluralism, and find them to be unsuccessful. This tension is a serious challenge that needs to be addressed in Cohen’s theory of justice.