The study about Nostoc HS-20 biomass growth in NPK fertilizer solved in spring water of Laboratorium Alam FMIPA UI (Lab. Alam water) had been done. This research was done to discover the optimum concentration of NPK fertilizer for viability and biomass growth of Nostoc HS-20 isolated from Mount Pancar hot spring, Indonesia. Nostoc HS-20 was cultivated in two set of Indonesian (local) NPK fertilizer which were 30:6:8 and 20:20:20. The concentration of NPK fertilizer media were 80 ppm and 240 ppm for 30:6:8 local NPK, then 125 ppm and 375 ppm for 20:20:20 local NPK. BG-11 and Lab. Alam water were used as control medium. This research was conducted for 14 days with two replication. The average of dry weight Nostoc HS-20 biomass after 14 days of observation was obtained at BG-11 was 0.0194 g/mL, Lab. Alam water was 0.0106 g/mL, 30:6:8 NPK 80 ppm was 0.0114 g/mL, 30:6:8 NPK 240 ppm was 0.0064 g/mL, 20:20:20 NPK 125 ppm was 0.0174 g/mL, and 20:20:20 NPK 375 ppm was 0.0151 g/mL. The result of 14 days observation showed that Nostoc HS-20 could grow in both of set of NPK and Lab. Alam water. The highest dry biomass production of Nostoc HS-20 was obtained at 20:20:20 NPK in concentration 125 ppm at day 7 on observation. This research showed that local NPK fertilizer dissolved in Lab. Alam water can be used as growth media for Nostoc HS-20 biomass production as a potential biofuel feedstock.