The only enzyme that is able to fix nitrogen, nitrogenase, reduces inert and abundant dinitrogen (N2) into bioavailable ammonia (NH3) under ambient conditions. The most investigated variant, the MoFe nitrogenase, uses three metallo-cofactors: the [Fe4S4] cluster in the electron-carrier component (Fe protein), as well as the [Fe8S7] (P-cluster) and [MoFe7S9C] (M-cluster) clusters in the catalytic component (MoFe protein). To better understand the physical properties of these cofactors, various methods have been developed for the chemical synthesis of model metal-sulfur clusters. In this review, we address the following topics with emphasis on recent developments: (a) the synthesis of all-ferrous [Fe4S4]0 clusters, which are isoelectronic to the super-reduced state of the cluster in the Fe protein, (b) the reproduction of the unique [Fe8S7] inorganic core of the P-cluster, and (c) the synthesis of metal-sulfur clusters relevant to the M-cluster and their variants that incorporate a light atom. Even though reproduction of the M-cluster remains elusive, some recent advances seem promising toward new classes of metal-sulfur clusters that satisfy the key structural features of the M-cluster.