Chronotherapeutic drug delivery system is useful in the treatment of disease, in which drug availability is timed to match rhythm of disease, in order to optimize therapeutic effect and minimize side effects. There is an impact of circadian rhythms in the symptoms of certain diseases like asthma, arthritis, depression, ulcer, allergic rhinitis, sleep disorders etc. The human body follows the solar/ lunar adaptations known as biological clock. The role of circadian rhythms in the mechanisms of disease and the pharmacokinetics and pharmacodynamics of medications constitutes a challenge to drug-discovery and drug-delivery scientists. We must strive to develop intelligent drug-delivery systems that can affect a target cell or organ system at that circadian time when it is possible to optimize desired therapeutic outcomes and minimize or avert adverse effects. The present article covers findings about the effects of biorhythms on various disorders, and their implications for drug therapy are discussed. Here we also reviewed the design of novel chronopharmaceutical drug delivery systems that might be able to release the therapeutic agents at predetermined intervals. Keywords:Chronotherapy, Circadian rhythm, Chronopharmaceutics, Chronopharmacokinetics.