Objectives: The objectives of the study were to determine the difference of concentration and expression of α-crystalline protein in white and brunescent cataract lenses. Methods: The design of this study is cross-sectional comparative. The subject was cataract patients who underwent cataract surgery in Puskesmas Pariaman, West Sumatra, Indonesia. Lens examination was carried out at the Microbiology Laboratory of FK Unand from July 2019 to February 2020. The samples consisted of 36 subjects who met the inclusion criteria. ELISA examination was used to determine the concentration of α-crystalline protein and Western Blot examination was performed to see the expression of the α-crystalline protein in all subjects. Results: The difference in the concentration of α-crystalline protein in white cataract and brunescent cataract was not statistically significant, with p=0.129 (p>0.05). The result of Western blot examination was normal expression of α-crystalline protein in white cataract and under expression of α-crystalline protein in brunescent cataracts. Conclusion: The expression of α-crystalline protein appeared to be different between white and brunescent cataract lenses. In brunescent cataract, under expression of α-crystalline proteins was related to the decrease of chaperone activity. This change occurred allegedly because of photochemical reaction that happened inside the lens.