Objective: This study aims to examine the structure of communication about complementary medicine (CM) between patients with cancer and clinicians during oncology consultations. Methods: Previously, consultations between 29 clinicians and 80 patients with advanced cancer were recorded in six hospitals in the Netherlands. The present study considers a secondary analysis. References to CM during the consultation were coded using a self-developed observational coding scheme. Results: At least one reference to CM was observed in 35 out of 80 consultations (44 %), with a total of 73 references. In most cases, CM was initially referred to by patients. Clinicians often did not elaborate on the subject of CM. Relevant aspects related to CM (e.g., safety, effectiveness) were infrequently discussed. Both patients and clinicians showed predominantly neutral to positive attitudes towards CM. Conclusions: This study shows that patients are still the main initiators of discussions about CM and the topic is not consistently discussed in daily oncology practice. Practice implications: If exploration of patients' interest in CM or its use became routine in oncology practice, it may relieve patients of the burden of introducing the topic, decrease potential risks of CM use and increase access to evidence-based CM for all patients with cancer.