The objectives of this study were based on screening for presence of decarboxylase producing microorganisms (Enterobacteriaceae, Enterococci and Lactobacilli) in sour milk, yoghurt and labenh, collected from supermarkets in Ismailia City. The isolated strains were tested for decarboxylase activity and the levels of histamine, tyramine, putrescine and cadaverine were determined in the examined samples. The results revealed that all the examined samples were contaminated with EnterobacteriaceaeandEnterococci at variable counts. All the isolated strains of Enterobacteriaceae, Enterococci and Lactobacillus spp. have the potential to release decarboxylase enzymes with biogenic amines formation. The examined samples were found to contain the estimated amines with variable levels, expect yoghurt that didn't contain tyramine. In conclusion, there was a positive correlation between the type of microorganisms present in fermented milk and the type of biogenic amines formed. The prevention of biogenic amines formation in fermented milks could be achieved by following good hygienic measures and careful screening of lactic acid bacteria for amino acid decarboxylase activity before selecting as starter or probiotic strains in dairy industry.