Seventy- five bulk tank milk samples collected from differentdairy farms in Sharkia govemorate. A survey was conducted todetermine the incidence of Coliforms, Pseudomonas spp. and Yersiniaspp. in bulk tank milk.All milk samples proved to be contaminated with Coliformsusing MPN Iml. Coliform count ranged from 2.0 x 104 to 2.1x 109 witha mean value of2.59 x 108 ± 6.lxl07.Escherichia coli could be detected in 21 ( 28% ) Citrobacterfreundii 20 ( 26.7% ), Citrobacter divers us 2 ( 2.67% ), Klebsiellapneumonae 12 ( 16% ), Klebsiella oxytoca 10 ( 13.3% ), Enterobacteraerogenes 6 ( 8% ), Enterobacter intermedium 3 ( 4% ) and Enterobactergergovae 1 (1.33 %) of the examined bulk tank milk samples.Out of 21 isolated Escherichia coli obtained from examined bulktank milk samples; 12 ( 57.1 % ) were fecal type and 9 ( 42.9% ) werenon- fecal type.14.67 % of the examined bulk tank milk samples werecontaminated with Yersinia spp.Yersinia enterocolitica could be detected in 3 and Yersiniapseudotuberculosis in 8 of the examined bulk tank milk samples.