Objective: Patients treated for multiple myeloma often suffer from anxiety and depression related to concerns about the future. This indicates a need for improvement of communication between patients and healthcare professionals within haematology. The aim of this study was to explore how patients with multiple myeloma and their caregivers experience serious illness conversation focusing on illness understanding, concerns, values, and wishes for the future. Methods: Phenomenological, semi-structured dyad interviews were carried out in patients with multiple myeloma (n = 12) and their caregivers (n = 11) 2–20 days after participation in one serious illness conversation. interpretive phenomenological analysis was used for analysing data. Results: Three themes emerged (1) transforming patient–caregiver communication, (2) redeeming communication, and (3) equality in communication in an unequal relation. Furthermore, time allocated for the conversation and preparatory materials for the conversations highly influenced outcome. Conclusion: The findings suggest that serious illness conversation can help patients and family caregivers managing living life with multiple myeloma by increasing dyadic communication and strengthen their use of existential language together with healthcare professionals. This study highlights the benefits of preparing patients and caregivers prior to the conversation and cancer care systems should strive to allocate ample time for serious illness conversations.