Aim The aim of this study was to describe the general attributes and competence that nurses in the ambulance's single responder units are considered to need. Background The development of ambulance care has led to an increased need for new units and working methods. Single responder unit is a single crewed unit that often uses for the patient assessments, to refer patients to the right level of care and to release regular ambulances. There is a lack of description of the needed competence for the nurses within single responder unit. Methods Modified Delphi with three rounds was used. The first round was conducted with focus group interviews and analysed with content analysis. The second and third rounds were conducted through surveys using a 4-point Likert scale and analysed with descriptive statistics. Results Five competence categories were identified. 39 of 80 statements reached consensus. The ability to communicate with other actors to achieve one’s goal, the ability to create a good encounter alone and to have appropriate professional experience were identified as the most important general attributes and competencies. Conclusions Increased understanding of the needed competence within single responder unit can be implemented in prehospital recruitment and education. Further research on the function of single responder unit and the most appropriate formal competence of the emergency nurses in single responder units is needed.