Background: There are over two billion telephones in use worldwide. Yet, for millions of Americans with intellectual disabilities (ID), access to the benefits of cellphone technology is limited because of deficits in literacy, numerical comprehension, the proliferation of features and shrinking size of cellphone hardware and user interfaces. Developments in smart phone technology and PDA-based cellphones provide an opportunity to make the social and safety benefits of cellphones more independently accessible to this population. Method: This project involved employment of universal design and other specialised software development methods to create a multimedia cellphone interface prototype which was compared with a typical mainstream cellphone in a usability evaluation for individuals with ID. Participants completed a structured set of incoming/outgoing phone tasks using both the experimental and control conditions. Usability measurements included the amount of assistance needed and errors made in completing the cellphone use sequence. Results: A total of 22 individuals with ID participated in the research by engaging in a series of incoming and outgoing cellphone calls using both the multimedia cellphone prototype system and a mainstream Nokia 6360 cellphone. Test subjects required significantly less help (P = 0.001) and made significantly fewer errors (P less than 0.001) when completing eight calls using the specialised multimedia phone system as compared with the mainstream phone. Conclusions: The statistical evidence of both usability results provide promising evidence of the feasibility of implementing universal design and other specialised software development methodologies for increasing independent access to the benefits of cellphone technologies for students and adults with ID. Issues related to designing cognitively accessible interfaces, study limitations and future directions are discussed.