Background: Primary hypothyroidism is a common endocrine disorder, more so in an increasing UK ageing population. There is no qualitative research examining the older patient perspective of symptoms, treatment and self-management of hypothyroidism. Objective: In this study we explored the experience of hypothyroidism in older people and examined how this may influence their understanding and acceptance of diagnosis, treatment with Levothyroxine and the monitoring process. Design: We conducted semi-structured interviews with 18 participants aged between 80 and 93 years. Interview transcripts were analysed using a thematic approach. Results: The themes involved older individuals' knowledge about symptoms, confidence in diagnosis and understanding of clinical management regimen to understand hypothyroidism. Interpretation of the themes was informed by the Health Belief Model. Conclusion: Our findings can help to inform the development of interventions by treating clinicians and support staff to engage older patients in the long-term management of this chronic condition.