Despite many different methods used to diagnose Salmonella typhimurium, especially that depended on isolation and biochemical identification, but use technique, Fluorescence in Situ Hybridization (FISH), as one method from molecular fashion probe, has been developed and applied for the direct diagnosis of S. typhimurium in bacterial cell smears of pure cultures, or in formalin-fixed sections, and in paraffin-embedded tissue. Therefore, this study was designed to determine the single bacterial cells in the infected intestine, liver, and gallbladder by used (Sal-3 prop), through orally administered for lambs via stomach tube, with a volume of 0.5 ml contains (1x10⁸ cfu/ml S.typhimurium), after bacterial identification by cultures media mainly Salmonella chromogenic agar, and biochemical diagnosis by [Iraq-CDC/central public health laboratory (CPHL) in the Baghdad province]. So results were concluded that Sal3-prop of FISH technique, was a good instrument for fortuity S. typhimurium in the histopathological tissue sections.