The present study was aimed to investigate the bacterial causes of diarrhoea in calves with symptoms and sensitivity test for isolated bacteria. 120 feacal samples (50 diarrhoeic cows & buffaloe calves and 10 each of apparently health cows and buffaloe calves) their age ranged from birth up to 2 month old. The clinical symptoms of diarrhoeic calves were depression, weekness, partiel loss of appetite, some cases suffered from recumbeny and varing degrees of dehyderation, diarrhoea accompained with mucous or and blood with offensive odour. The bacteriological examination revealed 67(69.1%) and 30(30.9%) were single and mixed infection respectively. E.coli was isolated at incidence percentage 47(37%), Pseudomonas aeruginosa 20(15.75), Campylobacter 18(14.17%), Salmonella 14(11.03%), Proteus vulgaris 12(9.45%) and each of Klebsiella pneumoniae and Staphylococcus aureus 8 (6.3%). E.coli isolates were identified serologically into 13(O₁₁₉), 9(O₁₀₁), 8(O₂₆) and 5(O₅₅). Also Salmonella spp. was identified as 6 Salmonella typhimurium and 6 Salmonella enteritidis. In vitro sensitivity pattern of isolated strains proved that Enrofloxacin and Gentamycin and Chloramphenicol were the most effective drugs for most isolates.