An indirect competitive enzyme immunoassay of Enterobacter sakazakii has been developed. The rabbit polyclonal antibodies to heat-labile or heat-stable antigen of the type strain E. sakazakii CNCTC 5739^T were prepared for these purposes. The detection limits of enzyme immunoassays were within the range 0.6–14.4 × 10⁵ cells/ml. Antibodies raised to heat-labile antigen were serotype-specific. Although they contain non-specific IgG fractions binding periplasmatic and cytosol proteins, the interactions of these immunoglobulins are not manifested under conditions of ELISA developed.