Technical Abstract: In this study, the antimicrobial activity of oregano oil was investigated under different attachment conditions of Salmonella spp. to iceberg lettuce. Inoculated lettuce was either not dried or dried for 30 min, 60 min or 120 min, under either static air or moving air. Washing iceberg lettuce with 500 ppm oregano oil for 1, 5 and 10 min reduced the population of Salmonella spp. by (respectively) 1.3, 1.65 and 2.28 log cfu/g following the most challenging inoculation conditions, an inoculum drying period of 120 min under moving air. Across all inoculation conditions, increasing in the treatment time significantly increased the reductions in the populations of Salmonella spp. Browning and softening of the lettuce leaf surface was observed after 10 min of treatment with oregano oil. For each treatment time, attachment times and drying under static vs. moving air did not significantly affect the antimicrobial efficacy of the various oregano oil treatments. The results obtained in this study suggest that oregano oil can effectively reduce populations of Salmonella attached to lettuce leaf surfaces.