OBJECTIVES: To identify whether speech recognition outcomes are influenced by the choice of ear for cochlear implantation in adults with bilateral hearing loss who use a hearing aid in 1 ear but have long-term auditory deprivation in the other. STUDY DESIGN: Retrospective matched cohort study. Speech recognition results were examined in 30 adults with monaural sound deprivation. Fifteen received the implant in the sound-deprived ear and 15 in the aided ear. SETTING: Tertiary referral centers with active cochlear implant programs. PATIENTS: Adults with bilateral hearing loss and a minimum of 15 years of monaural sound deprivation who received a cochlear implant after meeting the traditional implantation criteria of the referral centers. INTERVENTION: Cochlear implantation with devices approved by the U.S. Food and Drug Administration. MAIN OUTCOME MEASURE(S): Paired comparisons of postoperative monosyllabic word recognition scores obtained with the implant alone and in the usual listening condition (CI alone or bimodal). RESULTS: With the cochlear implant alone, individuals who received the implant in a sound-deprived ear obtained poorer scores than individuals who received the implant in the aided ear. There was no significant difference, however, in speech recognition results for the 2 groups when tested in their usual listening condition. In particular, poorer speech recognition scores were obtained with the cochlear implant alone by individuals using bimodal hearing. CONCLUSION: Similar clinical outcomes of cochlear implantation can be achieved by adults with a long-term monaural sound deprivation when comparing the usual listening condition, irrespective of whether the implant is in the sound-deprived or in the aided ear.