Introduction: Patients with hematological malignancies frequently receive aggressive, poor-quality end-of-life care. In oncology, person-centred serious illness conversations conducted early in the illness trajectory, focusing on patients’ goals, values, and priorities, have been associated with improved end-of-life care and decreased symptoms of anxiety and depression. Yet, evidence of their impact in hematology remains limited. Aim: This study explores the association between receiving a serious illness conversation and the quality of end-of-life care and the timing of serious illness conversations in patients with hematological malignancies. Materials and Methods: Single-center retrospective study. Data on receipt of serious illness conversations and end-of-life care (hospitalizations, specialized palliative care referrals, place of death, receipt of anticancer treatment) were extracted from electronic healthcare records. Logistic regression, adjusted for sex, age, and diagnosis, examined differences between patients who did and did not receive a serious illness conversation. Setting/participants: The study included patients with hematological malignancies who died between 2020 and 2022 and received anticancer treatment within the last 12 months at a university hospital in Denmark. Results: Among 311 patients (median age 74 years, 43% female), 63 (20%) received a serious illness conversation. Patients receiving conversations had significantly higher odds of referral to specialized palliative care (OR: 2.67, 95%CI [1.44; 4.91]) and lower odds of receiving anticancer treatment within 30 days (OR: 0.19, 95% CI [0.10; 0.37]) and 14 days (OR: 0.21, 95%CI [0.09; 0.46) before death. Conclusion: Serious illness conversations are associated with reduced aggressive end-of-life anticancer treatment and increased referrals to specialized palliative care.