The authors have performed local density calculations for NaCrS 2 with the LMTO-ASA method. They have studied the electronic structure and ground state properties of NaCrS 2 in the 3R and the hypothetical 1T structure. The magnetic properties have been studied within the framework of the local spin-density approximation. They obtain a semiconducting antiferromagnetic ground state with a moment of 3 mu B per Cr atom. The electronic band structure is compared with photoemission and optical measurements.