Peptide aptamers are combinatorial protein molecules with specific bind affinity 
to given target proteins under intracellular conditions. The typical structure 
of peptide aptamers is a short peptide region inserted within a scaffold 
protein. The short peptide region is responsible for binding with its target 
protein and the scaffold protein helps to enhance the binding affinity and 
specificity through restriction on the conformation of the binding peptide. This 
unique structural feature allows peptide aptamers to bind with their target 
proteins with strong affinity and high specificity. Applications of peptide 
aptamers thus vary from in vitro detection of various proteins in a complex 
mixture to in vivo modulation on proteins and cell functions. Peptide aptamers 
have also been considered as therapeutic molecules because of their anticancer 
and antivirus activity. Due to the importance of peptide aptamers, a general 
review on the structure, selection and applications of peptide aptamers in 
biological study as well as in therapeutics will be presented in this paper.