An ultrasensitive, simple, and fast lateral flow immunoassay for Salmonella detection using gold nanoparticles conjugated with a DNA probe, which is complementary to the 16S ribosomal RNA and DNA of Salmonella, has been developed. The detection limit is 5fmol for the synthetic single-stranded DNA. For the Salmonella cultured samples, the nucleic acids from 10 7 bacteria were rapidly detected in 30min. After silver enhancement, the detection limit was as low as 10 4 cells which is lower than 10 5 bacteria cells, the human infective dose of food-borne Salmonella. Furthermore, the probes used in this study are specific to Salmonella compared to several other Enterobacteriaceae. This approach would be a useful tool for microbial detection regarding food safety or clinical diagnosis. It is also suitable for large-scale screening in developing countries because it is low-cost, sensitive, specific and convenient.