Abstract 55 Mn spin-echo NMR spectra of the magnetically ordered states of YMn 2 , Y 6 Mn 23 and YMn 12 intermetallic compounds and their field-dependence have been observed at 4.2 K. The analysis of the spectra of YMn 2 has suggested that YMn 2 is an antiferromagnet with a [111] easy direction of magnetization. This result is consistent with the neutron diffraction study of this material. In the YMn 12 compound, a field dependence of the 55 Mn NMR spectrum similar to that of YMn 2 has been observed. The hyperfine coupling constant associated with the Mn 3d moment is estimated to be 42.7 kOe/μ B in both YMn 2 and YMn 12 , whereas Y 6 Mn 23 shows a slightly larger value because of the ferrimagnetic transferred hyperfine field from the neighboring Mn moments.