Abstract: OBJECTIVE In recent years, many new pharmaceutically active proteins and peptides have been developed due to the progress of biotechnological techniques and genetic engineering. However, many of them require special formulation technologies to overcome drug-associated problems such as hydrophilic and instability. METHODS This review described that solid nanoparticles (SLN) have been sought as an alternative carrier for hydrophilic proteins and peptides under optimized preparation methods to incorporate the drug. RESULTS Formulation in SLN confers improved proteins stability, avoids proteolytic degradation, as well as sustained release of the incorporated molecules. CONCLUSION Thus, many important peptides and proteins have been incorporated into SLN and are currently under investigation.