Background: Due to conflicting results between major trials the role of prophylactic cranial irradiation (PCI) in stage IV small cell lung cancer (SCLC) is controversial. Methods: We obtained a list of 13 European experts from both the European Society for Therapeutic Radiation Oncology (ESTRO) and the International Association for the Study of Lung Cancer (IASLC). The strategies in decision making for PCI in stage IV SCLC were collected. Decision trees were created representing these strategies. Analysis of consensus was performed with the objective consensus methodology. Results: The factors associated with the recommendation for the use of PCI included the fitness of the patient, young age and good response to chemotherapy. PCI was recommended by the majority of experts for non-elderly fit patients who had at least a partial response (PR) to chemotherapy (for complete remission (CR) 85% of radiation oncologists and 69% of medical oncologists, for PR: 85% of radiation oncologists and 54% of medical oncologists). For patients with stable disease after chemotherapy, PCI was recommended by 6 out of 13 (46%) radiation oncologists and only 3 out of 13 medical oncologists (23%). For elderly fit patients with CR, a majority recommended PCI (62%) and no consensus was reached for patients with PR. Conclusion: European radiation and medical oncologists specializing in lung cancer recommend PCI in selected patients and restrict its use primarily to fit, non-elderly patients who responded to chemotherapy.