Social media networks such as Facebook offer a promising way of fast, cost-effective and direct communication between enterprises and stakeholders. Employing this technology in entrepreneurial Public Relations (PR) may increase the success of new ventures. Yet, the adoption of social media for PR by start-ups remains under-studied. To fill this gap, we conceptualize entrepreneurial PR within the framework of communication management theory and entrepreneurial marketing. We developed three success factors for PR communication out of the literature and tested them empirically using a sample of 453 German start-ups. Results indicate that social media PR positively contributes to communication outcomes in terms of building up brand and reputation. Perceived relevance, long-term planning and understanding-oriented PR were all relevant for communication success. This means that entrepreneurs benefit from social media, when they initiate dialogues with stakeholders, conduct environmental scanning processes, and build up PR planning skills. Moreover, findings indicate that social media PR is practiced differently depending on the start-ups' age. Hence, it is crucial for future research to integrate a dynamic perspective on entrepreneurial PR studies. RÉSUMÉ Les r eseaux de m edias sociaux tels que Facebook offrent un moyen prometteur de communication rapide, economique et directe entre les entreprises et les parties prenantes. Le recours a cette technologie dans les relations publiques (RP) peut accroître le succ es de nouvelles entreprises. Pourtant l'adoption des m edias sociaux aux fins de relations publiques par les start-ups reste peu etudi ee. Pour combler cette lacune, nous conceptualisons les relations publiques entrepreneuriales dans le cadre de la th eorie de la gestion de la communication et du marketing entrepreneurial. Nous avons d evelopp e trois facteurs de succ es pour la communication dans les RP a partir de la litt erature et les avons test es en utilisant empiriquement un echantillon de 453 start-ups ARTICLE HISTORY