The microalga Tetraselmis is one of the marine species that use widely in aquaculture. This microalgae is capiable to absorbe and utilize the nutrients in the wastewaters and are as a source of unsaturated fatty acids. In this study, the mass culture of alga Tetraselmis tetrathele was investigated using the milk and yeast wastewaters for assessment of growth, viability and fatty acids composition. The experiment was carried out as compeletely radome design with six different treatmens including; Conway, milk and yeast all in the two different concentration of low (5 ml/l) and high (10 ml/l) for 11-days period. Result showed that this alga can culture on the low milk and yeast wastewaters, but the highest cell density (6.68 ×10 6 cell/ml); viable cells (3.83×10 6 cell/ml) and maximum SGR (2.84 /day) were obtained in the diulated yeast. The cell viability in the T. tetrathele cultured on diluted milk and highest percentage (up to 100 %) compared to other treatments. The protein and lipid contents were the highest in the concentrated milk treatment (44.6 % and 9.7% dry weight, respectively), while the carbohydrates was the highest in the concentrated yeast treatment (31.49 % dw). The protein, lipid and carbohydrate were ranged 10.7-44.5, 2.9-9.7 and 5.9-31.4 % dry weight, respectively. Based on fatty acids composition, the content of SAFA, MUFA and PUFA were 8.24, 94.45 and 16.37 % of total in concentrated Conway treatment; 23.1. 38.9 and 40.1 in diulated Conway; 70.81, 3.28 and 25.9 in concentrated milk; 53.76, 44.22 and 2.01 in diluted; also 41.41, 43.98 and 14.6 in concentrated yeast; 32.89, 37.46 and 29.78 in diulated yeast. In addition, the total content of n-3 and n-6 were obtained 2.1 and 15.1 for concentrated