The process of drug discovery is a long, slow, and painful journey. It is estimated that for approximately every 15,000 new compounds identified, only 5 will be considered safe for testing in human volunteers and 1 will be approved by FDA. Additionally, the road from preclinical studies to FDA approval can take more than 10 years and cost billions. However, there has been a big shift over the past decade to identify hit molecules. Predicting and optimizing protein-protein interaction became the key for drug design. Structural biology provides an exciting source of data that characterize interactions. By mimicking the interface through peptide, high affinity drug candidates can be developed. Additionally, high throughput methods of structure determination can provide powerful approaches to drug development. The continuous efforts of researchers and clinicians will lead to development of novel drugs that aid in the fight against deadly diseases. Here, three cases of efforts and achievements of peptide drug discovery are introduced. Considering the efficiency and selectivity, these peptides would perform as promising drug candidates with huge therapeutic potential.