The aim of this study was to set accurate and reliable methods in the identification of Enterobacteriaceae. In Micro CSB Entero each of a strip with 20 cupules containing dehydrated substrates for biochemical identification of bacterial species. Strips were inoculated with 100 microliters per cupule and incubated. After 18 hours, reagents were added. Baye's theorem was used to validate tests. Reactions from Micro CSB were cleared and easily read. 102 strains of Enterobacteriaceae were identified by MicroCSB--89.3% were correctly identified. 0.9% were identified with other tests 9.8% were incorrectly identified MicroCSB gives many advantages: This method save time, space and is less expensive than the other methods and it gives security for identifying species belonging to the different genera.