This study was designed to determine if rapid Salmonella infection is possible during the pre-slaughter holding period at swine abattoirs. For 24 groups of pigs studied in 2 high capacity abattoirs, pooled fecal samples were collected from the transport trailer right after pigs were unloaded (pre-holding samples). Holding pens were sampled prior to the entry of study pigs for the pre-slaughter holding. After slaughter, cecal contents and ileocecal lymph nodes were collected from 30 pigs in each studied group (post-holding samples). From all holding pens sampled (100%) at least one Salmonella serovar was isolated. All groups of pigs were Sa/monel/a-positive in the post-holding sampling, including those groups Salmonella-negative in the pre-holding sampling. Some groups had Salmonella serovars that matched serovars isolated from the holding pens, but not with serovars isolated from the pre-holding samples. Results indicate that the abattoir holding pens constitute an important source of Salmonella infections for swine.