OBJECTIVE: To explore the ways that patients and health professionals communicate about intimate and sexual changes in cancer and palliative care settings. DESIGN: A qualitative study using a three-stage reflexive-inquiry approach, with semi-structured, participant interviews (n = 82); textual analysis of national and international cancer and palliative care clinical practice guidelines (n = 33); and participant feedback at 15 educational forums for cancer patients or health professionals. SETTING: A large Australian public teaching hospital between 2002 and 2005. PARTICIPANTS: 50 patients diagnosed with cancer, and 32 health professionals who had worked in cancer and/or palliative care for a minimum of 12 months. MAIN OUTCOME MEASURES: Communication about intimacy and sexuality: patients' needs and experiences and health professionals' attitudes and experiences. RESULTS: There were mismatched expectations between patients and health professionals and unmet patient needs in communication about sexuality and intimacy. Most patients sought information, support and practical strategies about how to live with intimate and sexual changes after treatment for cancer, even if their cancer type did not affect fertility or sexual performance. In contrast, many health professionals assumed that patients shared their professional focus on combating the disease, irrespective of the emotional and physical costs to the patient. Health professionals overwhelmingly limited their understanding of patient sexuality to fertility, contraception, menopausal or erectile status. Many stereotypical assumptions were made about patient sexuality, based on age, sex, diagnosis, culture, and partnership status. There was a relationship between providing patient-centred communication about intimacy and sexuality and health professionals' understanding of their own attitudes and beliefs. CONCLUSION: Resources are needed to help health professionals engage in an exploration of their own definitions of intimacy and sexuality and understand how these affect interactions with patients with cancer.