Recently a meta-analysis showed an improved survival probability of prophylactic cranial irradiation (PCI) in limited disease small-cell lung cancer (LD SCLC) in complete remission after chemotherapy. We evaluated treatment results of PCI+ and PCI- in these patients. Whether PCI (n = 65) or no PCI (n = 37) was administered did not depend either on patients or on tumour characteristics. After 2 years the incidence of brain metastases was 11% in PCI+ patients and 51% in PCI- patients. Both disease-free survival and overall survival were significantly longer after PCI. PCI reduces the incidence of brain metastases, prolongs brain metastases-free period, and overall survival in LD SCLC patients in complete remission after chemotherapy.