The determination of rare earth elements (REEs) by ICP-OES in geological samples, containing iron at levels greater than 5% (0.5 mg/mL in final solution) is subjected to spectral or matrix interference. The interference is serious in case of Lu, Gd, and Tb, but relatively less for Sm, Yb, Pr, Tm, and Er. Dy an Ho do not suffer spectral interferences, but the iron matrix suppresses their signals almost completely at low levels (0.05 mg/mL or below). The interference prevails on most of the emission lines with adequate sensitivity for REEs, obviating the need for separation of iron from REEs. Iron is qualitatively separated by solvent extraction with methyl isobutyl ketone (MIBK) to bring its concentration in the solution under tolerance level. The separation is rapid, easy to manipulate, without any appreciable loss or addition of REEs to the matrix as compared to the separation of REEs as oxalate with calcium as carrier as recommended by some authors. The aqueous phase containing REEs is evaporated to dryness, treated with a few drops of HClO4 and finally digested in 0.5 M HCl. The solution obtained is aspirated into the argon plasma for the determination of REEs. The method has been applied to iron-rich geological samples, international geostandards SY-2 and SY-3, and a few pre-analyzed in-house samples after spiking with known amounts of iron (at levels usually found in magnetites and hematites). The REE values obtained in international geostandards and in-house samples were found to be in good agreement with reported values.