ObjectiveThe primary aim of this study was to investigate whether an information leaflet with illustrations and accompanying text about hearing aid functions have additional effects on participants' knowledge compared to an information leaflet without illustrations. An additional aim was to evaluate hearing aid users' knowledge of placement in a noisy environment, directional microphones and telecoil functions at baseline and postintervention and to assess the benefits of an information leaflet.Design and study sampleIn this RCT study the participants were randomised to the intervention group (n = 32) that received leaflets with text and illustrations and to the control group (n = 29) that received leaflets with text only. Open-ended questions were used to assess knowledge at baseline and after three weeks. Post-intervention benefits were evaluated by assessing statements about the leaflet.ResultsNo statistically significant differences in knowledge improvement were found between groups. Regardless of group allocation, participants showed limited knowledge at baseline and significantly improved knowledge postintervention. The participants reported the benefits of the leaflet regardless of group allocation.ConclusionsAn information leaflet about hearing aid functions increased participants' knowledge regardless of the presence of illustrations. Further research should be conducted to investigate how to design and use information leaflets in aural rehabilitation.