This paper presents data on the Dutch translation of the International Outcome Inventory for Hearing Aids (IOI-HA). The inventory was used as an additional postal tool in a nationwide study on the benefits of bilateral hearing aid fitting. Responses of 505 hearing aid users were analysed. Descriptive statistics and inter-item correlations are reported. Factor analysis resulted in the extraction of two factors. Cronbach's alpha coefficients and corrected item total correlations showed high internal consistency of the scales. Significant correlations were found between IOI Factor 2 and the Hearing Handicap and Disability Inventory and subscales of the Amsterdam Inventory for Hearing Disability and Handicap.