Personalized medicine promises to revolutionize the patient treatment by offering tailored medical services to the individual characteristics of each patient. It can improve the patient outcomes by reducing prescription errors and minimizing adverse drug reactions, as it focuses on prevention rather than reaction. The large volumes of data collected and processed by IoT-DS-AI nexus offers a unique opportunity to medical experts for developing customized treatment plans. Conventionally, the diagnosis and treatment have always been developed based on the population averages, which may not be fully effective for everyone.; however, use of smart technologies have eliminated this limitation, by providing an individual insight into genetic makeup, medical history, lifestyle factors and environmental influences. The wearable and ambient devices help to collect large amount of data from patients, which are then fed into advanced DS and AI models for developing personalized plans. This chapter first sheds light on the limitations of traditional medicine, followed by factors used for developing personalized medicine, such as genetic makeup, medical history, lifestyle, and environmental influences. Subsequently, the deployment protocols of IoT, AI and DS for developing personalized medicines are described and finally, ethical challenges associated with the domain are discussed.