The effects of compressor action, which reduces the long-term dynamic range of speech, on intelligibility of monosyllabic words presented in quiet was investigated. Three ratios of change in input level to change in output level were used, namely, 1-tol-dB, 2-to 1-dB, and 3-to ldB. Peak powers of the speech signals were adjusted for these 3 conditions of reproduction so as to achieve presentations of 0, 8, 16, and 24 dB sensation level. The interphonemic dynamic range of the speech signal was the variable under study. Performance of the normal hearers, patients with labyrinthine hydrops, labyrinthine otosclerosis, and presbycusis improved only slightly during either condition of compression. Moreover, the subjects with hearing loss did not achieve any greater benefit from compressor action than did normals. Neither the 2-to 1-dB nor the 3-to 1-dB compression ratio offered any important advantage over 1- to 1-dB reporduction when comparison was made only in terms of intelligibility at a given sensation level of the output signal.