Chronotherapeutics drug delivery system is useful i n the treatment of disease, in which drug availability is timed to match rhythms of disease, in order to optimize therapeutic effect and minimize side effects. The specific time that patie nts take their medication is very important as it has significant impact on success of treatment. If symptoms of a disease display circadian variation, drug release should also vary over time. Drug pharmacokinetics can also be time- dependent; therefore, variations both in a disease state and in drug plasma concentration need to be taken into consideration in developing drug d elivery systems intended for the treatment of disease with adequate dose at appropriate time. Var ious technologies such as time-controlled, pulsed, triggered and programmed drug delivery devi ces have been developed and extensively studied in recent years for chronopharmaceutical dr ug delivery. These, as well as pertinent issues, are addressed in this review.