The objective of this chapter is to introduce the hypnotics and sedatives. Sedatives are agents which depress central nervous system (CNS) activity producing a calming effect or drowsiness. Hypnotics are agents which facilitates the onset and maintenance of sleep. This chapter covers the history, classification, mechanism of action, comparative study of commonly used drugs, and therapy of insomnia. Insomnia is defined as difficulty in initiating and/or maintaining sleep. Insomnia may be primary or secondary due to depression, anxiety, mania, disease states or substance abuse. Drugs used in insomnia are benzodiazepines, non-benzodiazepines or z-compounds, melatonin agonist, and sedative antihistaminic.