Microalgae have emerged as one of the most promising sources for fatty acids production. Since the various fatty acid profiles (chain length, degree of unsaturation, and branching of the chain) of the different sources influence biodiesel fuel properties, it is important to possess data on how the presence of NaNO₃ as nitrogen source can influence the profile of produced fatty acids from algae. The fatty acid profiles of Desmodesmus quadricaudatus and Chlorella sp. were detected in batch cultures experiments. BG-11 nitrogen free medium or the medium contained 1.5g NaNO₃l^-1 were used in this investigation. At late stationary growth phase in nitrogen free medium, Chlorella sp. produced 58.39% saturated fatty acids and 41.60% unsaturated fatty acids. While in medium contained 1.5g NaNO₃ l^-1 produced 62.08% saturated fatty acids and 37.92% unsaturated fatty acids. In nitrogen free media D. quadricaudatus produced 66.92% saturated fatty acids and 33.07% unsaturated fatty acids. While in cultures contained 1.5g NaNO₃ l^-1 produced 51.62% saturated fatty acids and 48.37% unsaturated fatty acids. The fatty acid profile of Chlorella sp. that isolated from Egyptian water body and grown in nitrogen free media may suitable for biodiesel production. The results discussed and compared to fatty acids profiles produce by other algal species.