This study was carried out to survey the keeping quality in UHT (ultra-high temperature) treated milk stored at room temperature for 6 months from August 2000 to February 2001. The UHT pasteurized milk of A, B and C plant was treated at 130℃ for 2∼3s, 133℃ for 2∼3s and 135℃ for 4s, respectively. The UHT sterilized milk of A and B plant was treated at 140℃ for 2∼3s and 145℃ for 3∼4s, respectively. All of the raw milk samples collected from storage tank in 3 plants were showed less than 1×105cfu/ml in standard plate count, and normal level in acidity, specific gravity, and component of milk. Preservatives, antibiotics, sulfonamides and available chloride were not detected in both raw and UHT treated milk samples obtained from 3 plants. No bacteria were also detected in carton packs and tetra packs collected from 3 milk plants. One (10%) of 10 UHT pasteurized milk samples obtained from B plant and 2 (20%) of 10 from C were not detected in bacterial count after storage at 37℃ for 14 days, but all of the 10 milk samples from A were detected. No coliforms were detected in all samples tested. A total of 300 UHT pasteurized milk samples collected from 3 plants were stored at room (3℃∼30℃) for 3 and 6 months, 11.3% (34/300) were kept normal in sensory test, and 10.7% (32/300) were negative in bacterial count. The UHT pasteurized milk from A deteriorated faster than the UHT pasteurized milk from B and C. Therefore, this results indicated that the aseptically produced milk without contamination from the filling machine after UHT pasteurization could be achieved a maximum shelf life of 6 months.