In this study, a polivalance vaccine (PECA) prepared from Escherichia coli serotypes 01, 02, 078 and 0101 were investigated to determine how effective to E. coli infections in broyler chicks. Chicks were subcutaneously vaccinated by PECA in 10th and 20th days in 0.2 ml and 0.5 ml doses, respectively. The other group was hold as controlled. Before and after vaccination, blood sampling was carried out at 10 days intervals and antibodies in the serum samples were detected for each serotype by micro serum agglutination test and existence of pilus antibodies by plate agglutination test. Ten day after vaccine application, chicks were challenged. By these trials, 10% of the chicks vaccinated once with PECA and 30% of the pullets from control group died. Mortalities in groups vaccinated twice and control died 5% and 20%, respectively. In conclusion, polivalance E. co//vaccine could be recommended in protection of broyler chicks to E. coli infections. However, it was also conidered a combination of PECA with inactivated Newcastle vaccine may be useful.