Background: Respiratory-borne infectious diseases can spread rapidly at mass gatherings. The 2009 Hajj took place during the influenza A (H1N1) pandemic. This study investigates factors associated with compliance with recommended influenza A (H1N1)-related health practices and behaviors among American pilgrims to the 2009 Hajj: receiving seasonal influenza vaccinations, receiving influenza A (H1N1) vaccinations, and behaviors intended to mitigate respiratory illness. Methods: American residents from Minnesota and Michigan completed anonymous surveys prior to and following travel to the 2009 Hajj. Surveys assessed demographics; knowledge, attitudes and practices (KAP) related to influenza A (H1N1); seasonal and H1N1 vaccinations; health-seeking behaviors; sources of health information; and protective behaviors during the Hajj. Results: Pre- and post-travel surveys were completed by 186 participants. Receiving seasonal influenza vaccination was reported by 138 (63%) respondents, and 80 (36%) reported receiving an influenza A (H1N1) vaccine. One hundred forty-four (79%) respondents reported engaging in protective behaviors during the Hajj to prevent illness. In multivariable models, greater perceived severity of influenza A (H1N1) before traveling was associated with: seasonal influenza vaccination (OR. =. 1.74, 95% CI. =. 1.14-2.62, p=. .01), influenza A (H1N1) vaccination (OR. =. 2.02, 95% CI. =. 1.35-3.02, p=. .001), and engaging in protective behaviors during the Hajj (OR. =. 1.62, 95% CI. =. 1.00-2.63, p=. .003). Conclusions: This study found that accurate knowledge of influenza A (H1N1) symptoms, transmission, and prevention was associated with greater perceived severity of influenza A (H1N1); and perceived influenza A (H1N1) severity was associated with engaging in recommended protective health practices. Understanding the barriers to and facilitators of compliance with recommended behaviors can help guide the development of tailored outreach strategies to mitigate the impact and spread of respiratory disease.