This chapter focuses on sedative‐hypnotic drugs that are sued to alleviate the condition of sleep disturbances. One‐third of our life is spent in sleep; the lack, of which, can cause serious physical, social, and psychological problems. This chapter describes the features of an ideal hypnotic drug and provides a classification of sedative‐hypnotic drugs currently in use. These include the barbiturates, benzodiazepines, halogenated sedative‐hypnotics, heterocyclic sedative‐hypnotics, antihistamines, and other sedative‐hypnotics. Individual members of all of these classes of drugs are discussed in detail. The chapter also describes the physiology of sleep and the sleep cycle, including the nonrapid eye movement and rapid eye movement sleep. A list of neurotransmitters and nonhypnotic drugs that have a direct and indirect action on the sleep cycle are provided. The pharmacology including the evaluation of sedative‐hypnotics are also given. The chapter refers to the discovery of one of the most frequently prescribed hypnotic drugs, Zolpidem. The chapter also examines structure‐activity relationships, recent developments, things to come, and available websites.