Objectives: The gut feelings of doctors can act as triggers and modulators of the diagnostic process. This study explored the existence, significance, determinants and triggers of gut feelings among Spanish general practitioners. Design: Qualitative study using focus groups. Thematic content analysis. Setting: Primary healthcare centres in Majorca (Spain). Participants: 20 purposively sampled general practitioners working in Majorca. Results: General practitioners were aware of the existence of gut feelings in their diagnostic reasoning process and recognised 2 kinds of gut feelings: a sense of alarm and a sense of reassurance. A previous physician-patient relationship and the physician's experience had a strong perceived influence on the appearance of gut feelings. The physicians attached great significance to gut feelings, and considered them as a characteristic of the primary care working style and as a tool available in their diagnostic process. The physicians thought that the notion of gut feelings and their relevance can be transmitted to students and trainees. They tended to follow their gut feelings, although they were not sure of their accuracy. Conclusions: Spanish general practitioners in our study recognise the presence and role of gut feelings in their diagnostic reasoning process. Future research should examine the diagnostic accuracy of gut feelings and how to teach about gut feelings in the training of general practitioners.