Powder neutron diffraction data for NiCr2S4have been collected over the temperature range 1.8=T=286 K. The Cr3S4structure (space groupI2/m) is adopted at all temperatures. Refinement of 286 K data (a=5.8954(14) Å,b=3.4066(8) Å,c=11.0589(22) Å,ß=91.362(4)°) demonstrates that the distribution of nickel and chromium cations between sites in a fully occupied metal layer and sites in an ordered vacancy layer is close to that expected for the normal structure type. Data collected at 1.8 K (a=5.8621(5) Å,b=3.4051(2) Å,c=11.0297(9) Å,ß=91.607(6)°) reveal the presence of long-range magnetic order, involving a doubling of the unit cell in both theaandcdirections. Cations in the fully occupied metal layer possess an ordered magnetic moment of 1.57(6)µBwhich is directed parallel to the cation layers. Cations in the vacancy layer have a moment of 1.36(8)µBwhich is directed toward the anion layers. The magnetic ordering temperature was determined as 180(5) K. These results are correlated with magnetic susceptibility and electrical conductivity data. © 1997 Academic Press.