It is shown that SraL sRNA (RyjA), a sRNA present in many bacteria, down-regulates the expression of the chaperone Trigger Factor (TF), encoded by the tiggene and one of the three major ribosome-associated chaperones. SraL interacts directly with the 5′ UTR of the tigmRNA a few nucleotides upstream of the Shine-Dalgarno region. This constitutes the first report of a small RNA affecting protein folding.