The possibility of utilizing blended wastewaters from different streams was investigated for cost-efficient microalgal cultivation. The influent of a domestic wastewater treatment plant and the liquid fertilizer from a swine wastewater treatment plant were selected as water- and nutrient-source wastewaters, respectively. The growth of Micractinium inermum NLP-F014 in the blended wastewater medium without any pretreatment was comparable to that in Bold's Basal Medium. The optimum blending ratio of 5-15% (v v(-1)) facilitated biomass production up to 5.7 g-dry cell weight (DCW) L-1, and the maximum biomass productivity (1.03 g-DCW L-1 d(-1)) was achieved after three days of cultivation. Nutrient depletion induced lipid accumulation in the cell up to 39.1% (w w(-1)) and the maximum lipid productivity was 0.19 g-FAME L-1 d(-1). These results suggest that blending water-and nutrient-source wastewaters at a proper ratio without pretreatment can significantly cut costs in microalgae cultivation for biodiesel production. (C) 2015 Elsevier Ltd. All rights reserved.