The fetus is known to be bacteria-free and is contaminated with bacteria during birth. We examined drug-resistant bacteria in feces of new-born infants to know the distribution of drug-resistant bacteria in a hospital. Among 76 infants examined, we could isolate drug-resistant strains of bacteria from 65 infants (86%). We collected 110 drug-resistant strains of Escherichia coli, Klebisella pneumoniae, and Pseudomonas aeruginosa, and could isolate 53 strains (48%) carrying R plasmids; they being 33R (TC. CM. SM. SA. APC) and 20R (TC. CM. SM. SA) plasmids. The data indicated that R plasmids with the same resistance patterns were distributed in a hospital, and new-born infants were contaminated with bacteria carrying R plasmids, although the contamination rate of drug-resistant bacteria in the intestinal flora was very low.-