We have attended to a comparative research between two commercial microsystems: Enterotube and Minitek in order identify the Enterobacteriaceae and a reference system given by the combination of the usual macromethods already used in our laboratory. We have examined 401 bacterial cultures of Gram bacillus which we trought to belong to Enterobacteriums, coming from clinical material (excrements, urine, pharyngeal swabs, vaginal swabs, urethral swabs and espectoration) we have received for the bacteriological diagnosis. 390 of 401 cultures have shown to be Enterobacteriums. The biochemical reactions they have given show that the Enterotube and the Minitek have, with the usual system a good accordance for the following tests: dextrose (acid and gaz) lysin and ornithine decarboxylase, production of H2S and indole, phenylalanine deaminase and urease; while we have some statistically significant discordances for the fermenting of lactose and the use of citrate. We have also significant discordances E/C for the fermenting of dulcitole while the ones of Minitek are acceptables. The notes recommend the use, in the specialized bacteriological laboratories, of the conventional tests.