Magnetometry and dilute 57Fe Mössbauer spectroscopy studies of RMn 2X 2 (X = Si or Ge, R = La, Ce, Pr, Nd, Sm and Gd) at temperatures 4.2–650 K yield the following results; Fe in RMn 2X 2 is nonmagnetic. It reveals the magnetic order in the Mn and R sublattices through transferred hyperfine fields. The compounds LaMn 2Si 2, LaMn 2Ge 2, CeMn 2Ge 2, PrMn 2Ge 2, NdMn 2Ge 2 and SmMn 2Ge 2, known to be ferromagnets with T C = 300–350 K, are antiferromagnetically ordered above their corresponding T C. Their T N values extend from 385 K (SmMn 2Ge 2) to 470 K (LaMn 2Si 2), similar to the T N values of the antiferromagnetic heavy rare earth compounds. At the ferromagnetic-antiferromagnetic phase transition, a sharp reorientation of the Mn magnetic moments relative to the crystalline axes occurs. In SmMn 2Ge 2 we find five magnetic phase transitions, T C(Sm) = 30 K and T C(Mn) at 105 and 345 K and T N(Mn) at 155 and 385 K. In this compound, a superposition of two six-line 57Fe Mössbauer patterns is seen between 90 and 155 K with changing relative intensities, indicating a competition of two easy magnetization axes, with an anisotropic transferred hyperfine field at the Fe nucleus. In NdMn 2Ge 2 we find four phase transitions, T C(Nd) = 21 K, T C(Mn) = 335 K, T N(Mn) = 415 K, and one more very sharp transition at 210 K, associated with a discontinuity in 57Fe hyperfine interaction parameters and a sharp drop in bulk magnetization; this seems to be a transition from pure ferromagnetism to canted antiferromagnetism. The results for antiferromagnetic CeMn 2Si 2, PrMn 2Si 2 and GdMn 2Ge 2 revealed no new phenomena and are in full agreement with previous magnetization studies. In GdMn 2Ge 2 the transferred hyperfine field at the 57Fe nucleus is smaller at 4.2 K (below the ordering temperature of Gd) than at 90 K, proving that the transferred hyperfine field from Gd is opposite to that produced by Mn.