Missionaries and others who travel to provide humanitarian aid or disaster relief must ensure their personal health and well-being before, during, and after travel. Preparation for safe and healthy travel is critical, particularly when individuals may be traveling to a resource-limited environment. Outbreaks of infectious disease have been documented among missionaries, including both short- and long-term missionaries. Recent examples include dengue infections in multiple groups of missionaries to the Caribbean. Missionaries may face challenges such as working long hours under adverse or extreme conditions, and medical missionaries may be exposed to infectious diseases as part of their work. Missionaries with medical backgrounds may also find themselves in the position of monitoring the health of other missionaries in their group. The Centers for Disease Control and Prevention offers recommendations and resources for safe and healthy travel.