From 85 natural isolates of the Salmonella typhimurium complex, including the Salmonella reference collection A (P. Beltran, S. A. Flock, N. K. Smith, T. S. Whittam, D. C. Old, and R. K. Selander, J. Gen. Microbiol. 137:601-606, 1991), 65 strains (76.5%) released 71 different temperate phages. Forty-three (93.5%) of 46 tested phages were able to transduce the chromosomal markers his(+) and trp(+) and the cloning vector pBR325.