In this study, the effect of sodium acetate (C2H3NaO2) and sodium nitrate (NaNO3) concentrations on proximate and fatty acid composition of Ulva rigida (C. Agardh) was studied. Two trials were carried out. In the first experiment, the C2H3NaO2 was used as an organic carbon sources and five different concentrations of C2H3NaO2 were added; 0.25, 0.5, 1, 2, and 3 g/l. In the second trial, at the beginning of the experiment, 1 g/l C2H3NaO2 was added all groups, but the nitrogen regimes of the groups were changed. Five different nitrogen concentrations were used; 0.2 g/(l d), 0.3 g/(l d), 0.4 g/(l d), 0.6 g/(l d), and 0.11 g/(l d). According to our results, U. rigida cultivated with C2H3NaO2 and NaNO3 can successfully be used for both animal and human nutrition. The fatty acid methyl esters results showed that fatty acid contents of U. rigida were influenced by carbon (C2H3NaO2) and nitrogen (NaNO3) concentrations. The saturated fatty acids levels of U. rigida cultured in different NaNO3 concentrations were very high. The results indicated that C2H3NaO2 and NaNO3 addition during the culturing had considerable affects on proximate and fatty acid composition of the U. rigida. Using both C2H3NaO2 and NaNO3 offers a balanced fatty acid composition for both animal and human nutrition.