The optimum N: P ratio of kitchen wastewater (Kw) and oil-extracted fermented soybean water (Sw) for cultivation of S. platensis (Nordstedt) Geiteler was evaluated. A Complete Randomized Design (CRD) was carried out with 22 treatments and 3 replicates: Zarrouk media (Zm), 10 dilutions of Kw and 11 dilutions of Sw. The water quality, biomass production and pigment content of S. platensis were determined every 5 days for a period of 15 days. The chemical properties of cultivated wastewater had pH 6.84-9.50. The optimum levels of N: P ratio (N: P ∼ 6: 1) for algal cultured in the 5% Sw and Zm, with biomass production of 0.90 gL-1 and 0.84 g L-1 (dry weight), respectively. The highest levels of β-carotene and C-phycocyanin of S. platensis, when cultured in 10%Sw with the optimum N: P ratio (N: P∼5.7: 1.0), were achieved 0.37 mg g-1 and 21.27 mg g-1, respectively. Implications for using S. platensis for β -carotene and C-phycocyanin production when cultured with 10% Sw are discussed.