The present study was aimed to investigate the bacterial causes of newly born lamb mortalities. Seventy samples were collected (20 apparently healthy, 40 diseased and 10 dead lambs) their age ranged from one day up to 3 months old. The clinical symptoms of diseased lambs were weakness, partial loss of appetite, diarrhoea and respiratory signs. The bacteriological examination revealed that 48 samples (68.6%) were positive for bacterial isolation and 30 (62.5%) and 18 (37.5%) were single and mixed infection respectively. E. coli was isolated at incidence percentage 23(31.9%), Pasturella spp. 16(22.2%), Salmonella spp. 13 (18.1%), Klebsiella spp. 8(11.1%), Staphylococcus aureus 6(8.3%), Streptococcus spp. 4(5.6%) and Pseudomonas spp. 2(2.8%). E.coli isolates were identified serologically into 5 (O₂₆), 7 (O₅₅), 4 (O₁₀₁) and 7 untyped strains. Also, ٍٍSalmonella spp. was identified as 6                      S. typhimurium, 4 S. montividio and 3 untyped strains. In vitro sensitivity test of isolated strains revealed that the most effective antibiotic were sensitive for Enrofloxacin, Cefotaxim and Trimethoprim sulfameth-axazole and should be used in treatment of diseased cases.