The inﬂuence of information and communication technology to health and medicine has increased in the past decades, with the introduction of “wearable” and mobile applications that allows the user to monitor and assess, even evaluate, his/her health status and health regimen. These technologies allow one to monitor his/her behavior and recording it as numerical data. Once behavior has been “quantified,” one can then make adjustments to it and see how the related data changes. Tis technology-mediated self-tracking movement created the process and condition that is now called Quantified Self. Quantified Self works on the principle that if you can measure it, you can change it! In the field of medicine and healthcare, Quantified Self aims to improve self-sensing, self-awareness and human performance within the digital health industry. Tis movement is driven by increasing health and fitness awareness, decreasing costs of sensors and wearables, miniaturization of physiological sensors, integration of sensors into consumer-end devices and accessories, rising share of ageing population, increasing incidences of chronic and lifestyle diseases, focus on prevention rather than cure, and increasing mobile and smartphone permeation, especially in the field of medicine and healthcare. While Quantified Self gives the individual the capacity to decide what to do with his/ her health and health regimen, it creates problem with autonomy and privacy especially in matters of data access and protection. Quantified Self generates data that becomes the basis for changes or adjustments in health and health regimens. Tis presents question related to accuracy of data and the capacity of the individual to analyze and interpret data soundly. Quantified Self can also produce conﬂict between professional diagnosis and personal opinion gained from wearable technologies. Tis paper outlines ethical conﬂicts inherent in Quantified Self and presents some recommendations on the its ethical use in light of autonomy and data protection ethics.