Out of 200 examined rectal swabs of diarrheic calves, 159 samples 79.5% were positive for bacteriological isolates. The recovered bacterial species were E. coli,    S. typhimurum, Campylobacter sp, Corynebacyerium sp, P. aeruginosa and            C. perfringens types A and B with incidence of 47.5, 9, 7.5, 6, 4 and 5.5%, respectively. Typing of C. perfringens by intradermal inoculation test in albino Guinea pig revealed that the incidence of toxigenic and non toxigenic strains were (81.9% and 18.1%) respectively. C. perfringens type A was the most predominant to type B with the incidence of  45.5% and 36.4% respectively. The serological serotyping of 95 E. coli isolates revealed thefollowing serotypes K99 (21.1%), O157 (17.9%), O111 (9.5%), O125 (11.6%), O119 (15.8%), O26(12.6%), O128 (8.4%)  and un typed E. coli (3.2%). In vitro sensitivity of the recovered E.coli isolates to different antimicrobial agents shows that, E. coli isolates were highly sensitivite to enrofloxacin, flumequine and tetracycline. In contrast, these isolates were found to be resistant to ampicillin, erythromycin, gentamicin, lincomycin and penicillin-G. PCR panel could help diagnosticians rapidly determine the causative agents for bovine diarrhea in the early stages of disease and help practitioners initiate appropriate treatments or interventions quickly. Using PCR technique to improve the results, in case of E coli O 157 for rfb gene the molecular bands appeared at 259 bp, E coli K 99 gene F41 it appeared at 314 bp, while in Salmonella typhmiurium flic gene at 559 bp .