This work focused on screening out and characterizing antibiotic producing Pseudomonas to develop a new antibiotics that can overcome the growing resistance of disease-causing microbes. Pseudomonas sp. BCNU 1204 strain was isolated from Chong-ok-san. Biochemical, physiological and 16s rDNA sequence analyses indicate that strain BCNU 1204 belongs to genus Pseudomonas. Strain BCNU 1204 exhibited antibiotic activity against a wide range of bacteria, especially methicillin-resistant Staphylococcus aureus (MRSA). The optimum culture medium was composed of 20 g proteose peptone, 10 g glycerol, 1.5 g K2HPO4, 1M MgSO4 and 1 L distilled water. The maximum productivity was gained after being cultured at 35℃, pH 7.0 for 4 days. The active metabolite was extracted using ethylacetate. The separation of the active ingredient and its purification was performed using both thin layer chromatography (TLC) and GC/MS. The minimum inhibitory concentration (MIC) of the purified antimicrobial agent were also determined as 0.25-0.5 ?g/disc. The purified antimicrobial agent was suggestive of belonging to phenazine antibiotic produced by Pseudomonas sp. BCNU 1204.