Synthetic oligonucleotides have been deduced and synthesized based on the sequence of a salmonella‐specific polynucleotide probe. Two oligonucleotide probes, ST4 and ST15rev hybridized to 93 and 92 strains respectively out of 93 strains of Salmonella analysed. ST4, however, cross hybridized to one of the 28 strains of 16 genera of Enterobacteriaceae tested. Based on sequence alignment, in 16 strains of Salmonella, of a 114 base pair region, a Salm. typhimurium specific oligonucleotide probe, ST22, was identified. In colony hybridization, this probe detected all 47 strains of Salm. typhimurium analysed without hybridization to 94 strains of other Salmonella serotypes and to 26 strains of non‐Salmonella bacteria.