Isolation and identification of mesophilic and psychrotrophic bacteria distributed in Korean refrigerated beef were attempted. Total isolated colonies were 192, and identified as 5 genera and 10 species. Among them, mesophilic bacteria were Enterobacter aerogenes, E. agglomerans, Serratia liquefaciens, Proteus mirabilis, and "psychrotrophic" bacteria were Pseudomons fluorescens, P. putida, P. pickettii, P. mendocina, P. stutzeri, Alcaligenes faecalis. Dominant species was Serratia liquefaciens as mesophiles, and Pseudomonas putida as psychrotroph.chrotroph.