One hundred and twenty random samples of raw buffalo's, cow's, goat's and sheep's milk (30 of each) were collected from different farmer's houses and dairy shops in Assiut City to be examined for the presence of Klebsiella organisms on MacConkey Inositol Carbenicillin agar. The results revealed that K. pneumoniae was the most prevalent species among the Klebsiella organisms isolated (10 and 13.33%) for buffalo's and cow's milks. K. oxytoca (66.6%) in cow's milk only, K. ozaenae (2.66, 3.33 and 3.33%) for buffalo's, goat's and sheep's milk respectively, K. planticola (6.66 and 6.66%) in buffalo's and cow's milk respectively and K. terrigena revealed 1.33% in buffalo's milk.  Klebsiella organisms isolated from raw milk of different animals were (18) 15%, and they were 26.66% for buffalo's and cow's milks.  Concerning the second part dealing with the effect of cold temperature (5±1°C) on the viability of K. pneumoniae in sterile butter samples revealed that, there is a gradual increase in the number of K. pneumoniae from 17x10⁸ cells/g as an initial count to 91x10⁸, 206x10⁸, 217x10⁸ and 224x10⁸ cells/g in the first, second, third and seventh day respectively.  While a remarkable decrease in case of freezing temperature (0°C) from 17x10⁸ cells/g as an initial count to 10x10⁸, 113x10⁷, 220x10⁵ and 37x10³ in the first, second, third and seventh day respectively. K. pneumoniae inoculated in sterile butter completely disappeared and could not be detected after the first week in both chilling and freezing temperatures due to the high acidity percentages which reach from 4.3% at the zero time to 4.3, 4.3, 4.5 and 6.5%. Most of the isolated K. pneumoniae strains were highly sensitive to Norfloxacin, moderately to Gentamicin and weakly to cefotaxime but were resistant to other antibiotics used.  The public health hazard and suggestive measures were discussed to prevent milk and milk products from contamination with Klebsiella organisms.