In order to determine the rare earth elements (REE) in rocks, by neutron activation analysis, a group separation, before irradiation, was developed. The brazilian geological standards BB-1 and GB-1, provided by Instituto de Geociencias da Universidade da Bahia, were analyzed. The method was based an acid digestion of the samples, cation exchange separation with a Dowex 50WX8 column and coprecipitation of the REE with calcium oxalate. Interferers like U, Th, Ta and Fe were eliminated. The concentration values of ten REE (La, Ce, Pr, Nd, Sm, Eu, Tb, Ho, Yb and Lu) were determined. The analysis of Pr brought a contribution to the knowledge of the REE contents in these geological standards, since there are not yet results in the literature. The other REE data obtained were compared with literature values and some discrepancies are discussed. (author).