Influence of carbon dioxide on the activity of psychrophilic bacteria in raw bovine milk was investigated. Also, some sensory characteristics of pasteurized milk which processed from raw milk preserved by CO2 were studied. Firstly, effect of CO2 addition to raw milk was compared with the acidification of raw milk to pH 6.2 with lactic acid and with control milk. The results showed partial inhibition in psychrophilic microorganisms count in CO2-treated milk compared to both lactic acid-treated and control milks during four days of study. Secondly, the effect of two low temperatures (4 and 10 °C) on reducing psychrophilic bacterial count was evaluated. The storage temperature affected the growth of psychrophilic bacteria in CO2-treated milk; the lower temperature was the best; samples stored at 4 °C showed better inhibition in psychrophilic microorganisms count in comparison with the samples kept at 10°C. Thirdly, organoleptic characteristics of pasteurized milk (65 °C/30 min) processed from raw milk treated with CO2 showed insignificant differences (p?0.05) in taste, aroma and colour between CO2-treated and control milks.