An extracellular protease-producing yeast strain, designated as CO-3, was isolated from fermented tea. The cells were spherical- to ovoid-shaped and 6.8–7.4×7.4–9.1 ώm in size. Optimal growth conditions were 25–30°C and pH of 5.0–6.0. The isolate was able to grow in up to 4%(w/v) NaCl and 5%(v/v) ethanol. This strain was identified as Sporidiobolus ruineniae based on the internal transcribed spacer regions including 5.8S rDNA sequence and partial D1/D2 domain of 26S rDNA sequence analysis. Optimal activity conditions of the crude protease fraction of S. ruineniae CO-3 were pH of 7.0 at 50°C. Protease production reached maximum when 1.0%(w/v) xylose, 1.0%(w/v) yeast extract, and 0.3%(w/v) K2HPO4 were used as the sole sources of carbon, nitrogen, and mineral, respectively.