An experimental investigation of isotopically selective ion heating has been carried out in a lithium plasma under ion cyclotron resonance (ICR) conditions. The isotopic components ({sup 6}Li{sup +} and {sup 7}Li{sup +}) were subjected to selective ICR heating in a plasma column of diameter 6 cm with an average plasma density 10{sup 12} cm{sup {minus}3}. A solenoidal rotating electric field (E {approx_equal} 0.5 V/cm), produced by a spiral four-phase antenna, was used to heat the ions. The energy of the heated ions reached 90 eV. Special probes were used to obtain samples of enriched lithium in which the concentration of the {sup 6}Li isotope was equal to 88% (the initial concentration of this isotope was 8%). 14 refs., 4 figs.