BACKGROUND: Telephone calls for emergency ambulances are rising annually, increasing the pressure on ambulance resources for clinical problems that could often be appropriately managed in primary care. OBJECTIVE: To explore and understand patient and carer decision making around calling an ambulance for primary care-appropriate health problems. METHODS: Semistructured interviews were conducted with patients and carers who had called an ambulance for a primary care-appropriate problem. Participants were identified using a purposive sampling method by a non-participating research clinician attending '999' ambulance calls. A thematic analysis of interview transcripts was undertaken. RESULTS: A superordinate theme, patient and carer anxiety in urgent-care decision making, and four subthemes were explored: perceptions of ambulance-based urgent care; contrasting perceptions of community-based urgent care; influence of previous urgent care experiences in decision making; and interpersonal factors in lay assessment and management of medical risk and subsequent decision making. CONCLUSIONS: Many calls are based on fundamental misconceptions about the types of treatment other urgent-care avenues can provide, which may be amenable to educational intervention. This is particularly relevant for patients with chronic conditions with frequent exacerbations. Callers who have care responsibilities often default to the most immediate response available, with decision making driven by a lower tolerance of perceived risk. There may be a greater role for more detailed triage in these cases, and closer working between ambulance responses and urgent primary care, as a perceived or actual distance between these two service sectors may be influencing patient decision making on urgent care.