The therapeutic significance of bioengineering proteins has increased dramatically as a new generation of pharmacological drug with a great potential in medical treatment. Protein engineering has improved the use of new non immunoglobulin affinity proteins. The designed ankyrin repeat proteins abbreviated as DARPins is a classical example. These molecules have smaller structural size, unlike immunoglobulins, but similar target affinity is of great significance. Such molecules get more binding specificity and greater thermodynamic stability. These attributes made DARPins a favorite player in diagnostics and therapeutics of cancer. How DARPins are improved into vigorous and versatile scaffold for binding protein and selected by ribosome and phage display along with related aspects is discussed in this review.