Persons with intellectual and developmental disability remain among the most vulnerable members of society and frequently face numerous barriers. This includes having poor access to health information systems (HIS), which may be further compromised by a lack of accessible HIS resources. To be more effective, HIS must be easily accessible and usable to be understood by users. The study explores the usability and accessibility of HIS that is used and accessed by people with mild intellectual and developmental disability. Through focus groups following which we drew on qualitative data, we explored and observed the accessibility and usability of HIS by men with mild intellectual and developmental disabilities aged between 18 and 35 years. The findings of our study show that there is substantial promise for using and accessing HIS by participants. However, we identified many barriers against and enablers for using and accessing these systems. We also identified some design requirements for developing health information system for persons with mild intellectual and developmental disability.