Hearing aids are the principal tool for rehabilitation of hearing loss, one of the most prevalent impairments among elderly adults, but cost-utility ratings for hearing aid use are limited. Cost-effectiveness analysis. A multistate Markov model was constructed to model 50- to 80-year-old patients moving between states, including normal hearing, mild, moderate, or severe hearing loss. Parameters assigned in the model are partly derived from the Medline source (1966-2005) and partly from data on hearing-impaired elders (n = 96) in a tertiary care center in Taiwan. To address uncertainty, most of the parameters were specified by distributions, rather than base-case values. A probabilistic approach with Monte Carlo simulations was performed to produce an acceptability curve, showing the probabilities of being cost-effective given threshold values of willingness to pay (WTP). Hearing-related quality-adjusted life-years and cost in US dollars and Euros. The incremental costs for gaining an additional hearing-related quality-adjusted life-years in women and men were US $13,615 (Euro 10,826) and 9,702 (Euro 7,715), respectively. The probability of being cost-effective increased to 53% in women and 65% in men given a WTP of US $12,000 (Euro 9,542). The probabilities of being cost-effective to reach plateau were 67% for women and 78% for men given a WTP of US $20,000 (Euro 15,904). By modeling different degrees of hearing loss with a multistate model, hearing aid use was demonstrated to be a cost-effective strategy to rehabilitate the hearing-impaired elderly. These results can assist policy makers in allocating health resources appropriately and effectively.