Background: Antifreezing activity is a phenomenon of great significance in food industry that affects the quality of frozen foods. As a solution, ice-binding proteins, more specifically antifreeze proteins, have been used to mitigate recrystallization. However, knowledge about the mechanism of ice recrystallization and the influence of antifreeze proteins is scarce. Results: In this work, model homopeptides of three amino acids (proline, arginine and lysine) were studied by means of differential scanning calorimetry through the determination of their thermal hysteresis activity, to see the influence of several factors on their secondary structure. It was found that model homopeptides formed polyproline II type secondary structure that was more stable at low temperature. In addition, thermal hysteresis activity was higher for peptides of intermediate lengths and for proline homopeptides. Conclusions: The study of homopeptides sheds light on the mechanism of antifreeze activity and will allow the design of new molecules with antifreeze properties to be used in diverse biotechnological fields. How to cite: Rojas R, Aróstica M, Carvajal-Rondanelli P, et al. Relationship between type II polyproline helix secondary structure and thermal hysteresis activity of short homopeptides. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.08.003.