Effects of different concentrations (200-600 mg/L) of sodium (Na+, provided as Na2SO4 and NaCl) and magnesium (Mg2+, provided as MgSO4 and MgCl2) supplement on lipid (biodiesel) production simultaneously with wastewater treatment by the oleaginous yeast Rhodosporidium toruloides were investigated using synthetic wastewater with the composition similar to the mixture of real distillery and domestic wastewater. When Mg2+ was supplemented as MgCl2 at 200 mg/L, both lipid production and wastewater treatment were enhanced. Compared to control without Mg2+ supplement on day 5, the biomass and lipid production increased from 6.48±0.69 g/L and 0.96±0.13 g/L to 7.78±0.58 g/L and 1.35±0.02 g/L, respectively. The removal efficiencies for COD and TP also increased from 72.09±3.32% and 19.57±2.51% to 79.20±1.13% and 23.19±3.07%, respectively. These increases were considered mainly due to the important role of Mg2+ in lipid synthesis, phosphate transfer, and carbohydrate metabolism. In comparison to Mg2+, the effect of Na+ depended on the supplement form. When 200 mg/L Na+ were provided as NaCl, maximum lipid production was 2.66±0.11g/L while only 1.98±0.63g/L when Na+ provided as Na2SO4. For a better lipid accumulation and wastewater treatment performance, the optimal concentrations of both Mg2+ and Na+ were considered around 200 mg/L.