The use of aptamers as targeting molecules has revolutionized nanomedicine. Aptamers are short oligonucleotides or peptides that can be used as targeting ligands against numerous targets. Aptamers are versatile moieties that can be used both in therapeutic and targeting applications. Aptamers bind to the target in a process that is similar to the lock and key mechanism. There are numerous reports on the use of aptamers as targeting moieties for imaging and drug delivery applications. In this review, we would like to give a comprehensive report on aptamers, its properties and the developments in aptamer mediated drug delivery in the recent years.