Customer comfort during service interactions is essential for creating enjoyable customer experiences. However, although service robots are already being used in a number of service industries, it is currently not clear how customer comfort can be ensured during these novel types of service interactions. Based on a 2 × 2 online between-subjects design including 161 respondents using pictorial and text-based scenario descriptions, we empirically demonstrate that human-like (vs machine-like) service robots make customers feel more comfortable because they facilitate rapport building. Social presence does not underlie this relationship. Importantly, we find that these positive effects diminish in the presence of service failures.