A variety of dibenzocrown ethers have been evaluated for the extraction of cesium from acidic nitrate media. Compounds incorporating a 21-crown-7 moiety are shown to exhibit greater cesium/sodium selectivity, superior functional stability, and better compatibility with PUREX-like diluents than dibenzocrown ethers with other ring sizes. The cesium distribution ratios obtained with these compounds, however, are generally not large enough to be of practical value. Higher Dcsvalues are achieved with several dibenzo-18-crown-6 derivatives. Of these, the best results are achieved with 4,4'(5')-di-[(l-hydroxy-2-ethylhexyl)benzo]-18-crown-6. The distribution ratios obtained with this compound in undiluted tri-n-butyl phosphate (TBP) compare favorably with those reported for synergistic systems combining a crown ether with the anion of a lipophilic organic acid.