Objective: To provide qualitative data on the men's experience, impact and relative importance of hot flushes as a result of prostate cancer therapies, with an emphasis on gonadotropin-releasing hormone (GnRH) agonists. Methods: A qualitative study applying a non-probabilistic purposive sampling strategy. Participants were over 50 years old with histologically confirmed adenocarcinoma of the prostate, had recently initiated (= 6 months ago) and were receiving GnRH with or without anti-androgen, and had recent experience of hot flushes as a result of their therapy. A content and thematic analysis was conducted to identify themes and categories that centred on particular phrases, incidents and types of behaviour. Results: Participants (n=12) aged 58-82, diagnosed on average for 5 years, receiving GnRH agonists (100.0% Lupron, 40.0% Casodex, 20.0% Zometa) were interviewed. The first hot flush usually occurred within 2 weeks of GnRH treatment. Participants experienced widely differing hot flush event frequency and severity; from 8-10 events in 24 hours to one in 2-3 weeks. Events lasted 2 minutes to one hour, and occurred at different times. Analyses identified that hot flushes were most commonly described in terms of ‘sweating', ‘burning up', and ‘perspiring'. Those who had more severe flushes also described ‘dizziness', ‘weakness', and ‘nausea'. Participants found their hot flush experience generally distressing e.g. felt scared, anxious, annoyed, confused, irritated, worried. Hot flushes impacted men's lives e.g. sleep problems, needing to stop activities, resting, taking a cold shower. However, most considered the hot flush experience in the context of their overall condition, some reported getting used to the experience over time and adopting varies coping strategies. Conclusion: Hot flush descriptions reflect those previously reported in the literature, provide additional depth to the experience from the patient's perspective and will inform the development of health states for utility assessment.