Dy₃Ni₂ is monoclinic, space group C2/m, with a=13.321, b=3.662, c=9.512 Å, p= 105.72 °, Z=4. Tb₃Ni₂ and the low-temperature modification of Ho₃Ni₂ are isotypic. The structure was solved by Patterson methods followed by a full-matrix least-squares refinement to an R of 0.08 for 538 counter reflexions. The structure is characterized by rare-earth trigonal prisms centred by Ni atoms. These prisms are similar to those found in the CrB-type structure and their arrangement is related to the CrB-type configuration.