First-principles computations were carried out to predict the stability and magnetic and electronic properties of MoS2 nanoribbons with either zigzag- or armchair-terminated edges. Zigzag nanoribbons show the ferromagnetic and metallic behavior, irrespective of the ribbon width and thickness. Armchair nanoribbons are nonmagnetic and semiconducting, and the band gaps converge to a constant value of similar to 0.56 eV as the ribbon width increases. The higher stability Of MoS2 nanoribbons, compared with the experimentally available triangular MoS2 nanoclusters, invites the experimental realization of such novel ribbons in true nanoscale.