In Nigeria, the mobile health trend is gradually improving and generally upgrading the way healthcare services are being rendered. Assessing the usability of these apps is still a major task as a result of the many attributes embedded in most usability models. In other to rank some of these attributes, a Multi-Criteria Decision Making technique (MCDM) was used. The attributes ranked were adopted from the Enhanced Usability Model (EUM) which was designed based on the People at the Center of Mobile Application Development (PACMAD) model and the Integrated Measurement Model (IMM). Attributes were ranked using their priority weights based on the Triangular Fuzzy Numbers (TFN) and Fuzzy Chang extent analysis model. Results of evaluation showed that effectiveness and efficiency had the highest priorities with 40% and 33% while satisfaction, user interface aesthetics and universality had the lowest ranks. Three mHealth apps were analyzed and results showed that Omomi had the highest ranking with a weight of 41%, Find-A-Med ranked second with a weight of 30% while Hudibia ranked lowest with a weight of 29%. In conclusion, it was established that the mathematical technique used is a powerful tool for analyzing human decision-making process. Future works would consider other MCDM models and comparisons done.