Amphora aff. amoena and Chaetoceros muelleri are potential diatoms with good proximal composition and the ability to grow rapidly. Like other microalgae, this composition can be improved by adjusting their culture conditions, such as exposure to different light conditions. However, there is still a need to explore these culture conditions further and their effect on these diatoms. This study aimed to evaluate the chemical-proximal composition of the diatoms A. aff. amoena and C. muelleri under three wavelengths: white (WL) range (400-750 nm), blue (BL) range (430-480 nm), and red (RL) range (595-660 nm), at an irradiance of 200 μmol m-2 s-1 using LED lights. In both species, A. aff. amoena and C. muelleri, the highest cell concentration under WL was: 216,250 and 1,198,125 cells mL-1, respectively. The carbohydrate content was 5.80% for A. aff. amoena and 2.21% for C. muelleri, while protein content was 13.41% for A. aff amoena and 12.31% for C. muelleri. Lipids were found to be most abundant in A. aff. amoena when exposed to RL (37.19%) and C. muelleri (60.48%) when exposed to BL. No significant differences were found in A. aff. amoena under different light conditions.