Background: Producing accessible information regarding health issues is very important in order to ensure that people with intellectual disabilities (ID) have equal access to services and can make informed decisions about their treatment. Method: This study examined whether an Easy Read leaflet improved service users' comprehension and compared the efficacy of two different modalities of presenting information: "text and pictures" or "pictures only". Participants' knowledge was assessed at baseline and immediately after the leaflet. Results: Our findings indicate that the use of the leaflet improved knowledge but neither modality of presenting information was significantly more effective at making the document easier to understand. Contrary to expectation, people with milder ID may find pictures more effective in the absence of text. Conclusions: Although pictures were not found to be detrimental, our results do not favour the use of pictures as well as text when giving information, particularly to people with milder disabilities. The generalised use of text and picture formats for all people with ID in spite of the scant evidence supporting its effectiveness is concerning.