Background: The depletion of fossil fuel reserves has stimulated the search for sustainable sources of energy that are carbon-neutral or renewable. In this context, microalgae are a promising energetic resource. They are photosynthetic microorganisms that use CO2 as carbon source, with high specific growth rates. Furthermore, some species present high lipid content that can be easily converted into biodiesel. Accordingly, this study aims to analyze the effect of light supply (one of the most important culture parameters) on lipid production of selected microalgae, chlorella vulgaris and Pseudokirchneriella subcapitata.Methods: Both microalgal species were cultured under different light irradiance values (36, 72, 96, and 126 mE m-2 s-1) and for each light irradiance value, three light/dark ratios (10: 14, 14: 10, and 24: 0) were tested. Lipid contents of both microalgae were then determined using a recently developed colorimetric method.Results/Conclusions: P. subcapitata presented higher lipid productivity than C. vulgaris. High lipid concentration was achieved in microalgal cultures with higher light irradiance values. However, for 96 and 126 mE m-2 s-1, lipid productions of both microalgae were not significantly higher than with 72 mE m-2 s-1, which means that microalgal light saturation point may be achieved.