Topoisomerases are class of enzymes that alter the super coiling of double-stranded DNA. (In super coiling the DNA molecule coils up like a telephone cord, which shortens the molecule.) The Topoisomerases act by transiently cutting one or both strands of the DNA. Topoisomerases are enzymes that regulate the over winding or under winding of DNA. The winding problem of DNA arises due to the intertwined nature of its double-helical structure. During DNA replication and transcription, DNA becomes over wound ahead of a replication fork. If left unabated, this tension would eventually stop the ability of the enzymes involved in these processes to continue down the DNA strand. Topoisomerase inhibitors are agents designed to interfere with the action of topoisomerase enzymes (topoisomerase I and II), which are enzymes that control the changes in DNA structure by catalyzing the breaking and rejoining of the phosphodiester backbone of DNA strands during the normal cell cycle. The present review is an attempt made in the respect of highlighting the some important information of Topoisomerase enzyme and topoisomerase inhibitors and role of topoisomerase in cancer therapy.