Abstract: Acids and salts are important environmental conditions encountered by Shigella spp. during its survivality and pathogenesis. These studies have shown that S. sonnei and S. boydii could survive longer than 120 min to acidic environment at pH 3 and approximately 32% survivality for both the species was recorded. The acid tolerance was found to be dependent on the growth phase and pH of the growth medium. Shigella spp. previously grown in low-salt broth at pH 7.2, produced organisms which were markedly more acid sensitive when subsequently cultured in the same broth supplemented with 200 mM or more salt at 37 °C. A differential survival pattern was recorded with salt-treated Shigella spp. in a number of aquatic samples. Fluorescent microscopic examination revealed that Shigella spp. treated with 500 mM salt went into non-culturable state but remain viable. However, salt treatment could produce no significant changes to the infective properties of Shigella spp.