Much efforthas been devoted to evaluating the usability of web-based system. With the increase in the mobile-based applications coupled with the limitations and challenges of mobile devices, it becomes mandatory to evaluate the web-based systems in the context of smartphone usability. In addition, a number of international standards/models on usability are available, but seldom used for practical usability evaluation. In this study, the popular ISO 9241-11 standard was used to evaluate a web-based health awareness portal within the smartphone mobile context. The results reveal some pointers to usability issues as well as confirmation that the web-based awareness portal is relatively usable on smartphone devices within the components defined in the models.