Distance learning is common in most segments of education, and the body of knowledge is extensive. Extension can apply much of this research but uniquely educates students whose presence is voluntary. The literature suggests that successful distance-delivered Extension courses share three characteristics: course content is high quality, demand is high for the course, and the distance-delivery method is satisfactory. More studies are needed to better assess the efficacy of specific distance-delivery methods in an Extension setting, but these three keys can be used to decide whether or not to deliver a course using distance delivery.