The contents of the individual lanthanide elements are determined by neutron activation using a new comparator technique, which employs the short-lived radio-isotope of 56Mn as a neutron flux monitor. The total rare earths are separated as a group from the monazite sample before irradiation. After irradiation the rare earths are separated from each other by gradient elution with ammonium alpha-hydroxyisobutyrate using a cation-exchange column. The contents of 14 individual rare earths, from lutetium to lanthanum, are deter-mined.