Aim: To investigate and gain knowledge about patients’ perspectives on everyday life with mastocytosis and how they experience, understand and manage symptoms and challenges. Background: Indolent systemic mastocytosis (ISM) is a disease characterised by the accumulation and activation of mast cells. Symptoms are diverse and range from mild to severely debilitating or even fatal. It is considered rare but is underdiagnosed due to lack of awareness. Quantitative studies have shown that ISM can negatively impact quality of life. No qualitative studies have described everyday life with the disease. Design: A qualitative interview study taking a phenomenological approach. Methods: Seven qualitative, semi-structured interviews with adult patients with ISM. The analysis was inspired by Giorgi's phenomenological method. COREQ reporting guidelines were used. Results: Three themes and five subthemes emerged from the analysis. (a) The everyday life with a rare disease, unknown to most people. Being perceived as a hypochondriac in the encounter with the health system. The diagnosis makes a difference. Expert knowledge is important. (b) Living with and handling the invisible and visible symptoms. The visible body. (c) Fearing an attack. Feeling safe and vulnerable at the same time. Conclusion: Patients with ISM are severely affected in their everyday lives, especially in terms of their relationship with family and social network. Symptoms restrict and complicate activities and participation in social contexts, and the fear of an anaphylactic attack is always present. The disease affects patients’ self-perception and sexuality. The rarity of the disease and general low awareness seems to be of great importance in the encounter with the healthcare system, both before and after diagnosis, and there is a need for expert knowledge, support and care. Relevance for clinical practice: The focus of counselling should not only be on the disease itself, but also on living life with the disease.