Context: Sensor base data is being used for many purposes in designing various memory aid systems for cognitive impaired people. Different memory aids or reminder systems are based on various technologies such as NFC, accelerometer, GPS and gyroscope. Smart phones are equipped with such sensors and can be used for assistance of persons. In this study we use smart phone sensors in order to design a context aware reminder system to assist cognitive impaired people. Objectives: Different reminder systems, needs for such systems, technologies and models used to build a reminder system are identified in this research work. Ultimate goal of the study is to assist cognitive people in their daily life activities, using available embedded technologies of smart phones. Following objectives were set to achieve the goal of the thesis work: • What are reminder systems and why do we need such systems? • What are the different kinds of technologies reported in literature for reminder systems? • What are the issues encountered by cognitive impaired/elderly people while performing their daily life activities? • How to design and implement context aware reminder system using Smartphone embedded sensors? Methods: Mix method approach is used to carry out this study. Literature review is conducted based on the notion of systematic review. Data is collected through survey and interviews, conducted in south Sweden municipality, to analyze and indentify daily life issues and problems of cognitive people. Experiments are performed in real environment to test and verify our application. We evaluate the performance of activity recognition algorithm, implemented in the application, using Weka. Results: Various reminder systems, their needs and underlined technologies are identified and reported. Activities of daily living and issues addressed by these reminder systems are also identified. Survey and interviews help us to identify issues and problems faced by cognitive impaired/elderly while performing their daily life activities. For example, we find out that cognitive people not only forget their daily life activities but also during performing these activities. Conclusions: Many proposed models in literature are related to each other and use similar sensor based data from various technologies. Based on literature review, survey and interviews we have concluded that context based reminder system is essential for cognitive disabled people. It leads us to design a context based reminder system for android based smart phones. The preliminary tests help us to verify our model but there is absolute need for further empirical verification and validation.