Algal cultures of Scenedesmus obliquus were grown in two different sewages (settled and activated). Both types of wastewater supported good algal production, which was comparable and even better than that found in the commercial Bristol medium. Much higher biomass production was recorded in settled sewage than activated sewage under semi-continuous culture condition. High correlation was recorded between algal growth and nutrient removal in both settled and activated sewages. The N⁺₄ — N dropped faster in the settled sewage from its initial 30.5 mg/ to 3.2 and 4.6 mg/I in the batch and semi-continuous cultures, respectively, after 8 days. Some fluctuations appeared in nitrate concentrations in both sewages. The rate of removal was significantly higher in the activated sewage in all treatments, and reached about 91%, removal. The changes in phosphate concentrations were similar in both sewages. There were increases in the first two days, then decreases, especially in the semi-continuous cultures. The maximum P removal (90%) was recorded in semi-continuous cultures in settled sewage. The results of this study suggest that the semi-continuous algal culture is more suitable and efficient in wastewater treatment than the batch cultures.