Abstract The magnetic susceptibilities of ternary rare earth compounds with the CaAl2Si2 structure were measured in the temperature range of 80 to 290 K. YbZn2Sb2 and the compounds YbZn2-x;CuxX2 (X = P, As) with x < 1 show intermediate valence behaviour, that is a nonintegral occupancy of the 4f shell. Of the compounds EuZn2X2 (X = P, As, Sb) the results for those with X = P or Sb show good agreement with the theoretical values for Eu(II). In LuZnCuAs2 and RELi2X2 (RE = Ce, Pr, Nd, Tb; X = P, As, Sb, Bi) the trivalent state of the rare earth atoms can be established. With the exception of LuZnCuAs2 the susceptibilities of all of the investigated compounds follow the CURIEWEISS law.