In Taiwan, group tours are a popular mode of international travel; hence, group tour leaders must ensure traveler safety and health. This study identified factors influencing tour leaders' willingness to recommend pretravel medical consultation and vaccination.A cross-sectional questionnaire survey was administered to tour leaders from January 2011 to December 2012. Multivariate logistic regression analyses were performed to estimate the odds ratios of having a positive attitude and willingness based on different knowledge scores of the tour leaders after adjustments for age, sex, education level, and seniority.Tour leaders with a more detailed knowledge of both travel-related infectious and noninfectious diseases demonstrated a higher willingness to receive vaccination. They believed that consultation at travel clinics before travel can improve travelers' health (P < .05).This study supports the importance and effectiveness on educating tour leaders' knowledge about travel-related diseases to improve health care for travelers.