A total of 75 random samples of pasteurized: milk, cream and Rayeb (25 samples of each type) were collected from different localities in Assiut City and examined for the presence of L. monocytogenes. The obtained results pointed out that L. monocytogenes could be isolated from 4% of the examined pasteurized milk samples, while could not be detected from pasteurized samples of cream and Rayeb. Furthermore, three trials on sterile milk which were inoculated with 37x10⁷ CFU/ml of L. monocytogenes as an initial count to detect the thermal resistance of the organisms when exposed to boiling temperature at different times. The obtained results of the three trials revealed that the number of the organisms decreased and reached to 274x10⁵, 214x10⁴ and 120x10² at the first, second and the third minute, respectively, while at the fourth minute the organisms could not be detected. The public health importance and the sanitary measures for control of the organisms were mentioned.