Human population bears a similarity to an extent of 99.9%, however mere 0.1% of variability also creates large differences in personal make-up owing to several hereditary and environmental factors. Conventionally, development of healthcare modalities like diagnostics and therapeutics has been by mass production assuming uniformity in characteristics of recipient population. Due to the inherent variability in each individual clinical response to diagnostic and therapeutic products vary greatly ranging from inefficient therapeutic compliance, adverse reactions and hypersensitivity reactions. Personalization of medications is the need of hour to avoid perils of both modalities so that efficient healthcare is provided to human population. Advances in delivery like targeted drug formulations, companion diagnostics and triggered drug formulations provide necessary dimensions to personalized medicines. Formulations with these capabilities can be described as theranostics and have been instrumental in this decade to establish the field of personalized medicine. The current chapter reviews different types, mechanisms of targeted and triggered drug delivery systems that have helped to improve the diagnostic and therapeutic compliance in disease management.