Strategies to curb infection of pigs by Salmonella are sought throughout the fann to table continuum. Competitive exclusion (CE), which involves colonizing the gastrointestinal tract of young animals with a healthy gut microflora, has been shown to be an attractive strategy for protecting poultry from salmonellae infections (4-7, 14, 16-17, 19-20, 23). More recent evidence suggests that CE may enhance resistance of young pigs against infections by Salmonella serovar Choleraesuis (2, 9, 15, 21), the serotype responsible for the vast majority of swine salmonellosis cases in the United States (22). Salmonella serovar Typhimurium can also infect and cause disease in swine and may be considered a greater food safety concern than Salmonella Choleraesuis but until now, reports regarding the effect of CE treatment on colonization resistance of early weaned pigs to this serotype have been few if not nonexistent.