OBJECTIVES: It has been argued that gain in health state valuation after intervention is smaller from a patient perspective than from a nonpatient perspective. In this study we use hearing impairment as a research model to test whether illness experience, personal or through medical experience, influences gain in health state valuation after hearing aid fitting. METHODS: The study consisted of a prospective study of fitting hearing aids in hearing impaired adults (N=96), with 2 measurements: before hearing aid fitting, and 12 weeks afterwards. On both occasions the patients valued and described their actual hearing related health state. Descriptions of the health states before and after hearing aid fitting were used to obtain valuations in: 1) healthy persons without any illness experience, 2) persons with medical experience with visual impairment, and 3) persons with medical experience with hearing impairment (N=26 each). Data were tested for between-group differences and influence of gender and education level using ANOVA. RESULTS: The valuations for the health states before and after hearing aid fitting differed between the groups (p=0.001 and p=0.011 respectively). The highest average valuations were observed in the group with medical experience with hearing impairment. The change in health state valuation after intervention was not different between the groups (p=0.295). Gender and education level did not influence the results. CONCLUSIONS: The results confirm that illness experience influences health state valuations. Although the study groups were relatively small and hence the results should be interpreted with some caution, as opposed to earlier findings in this study persons with experience through medical knowledge had higher valuations than patients, and change in health state after intervention was not influenced by illness experience.