BACKGROUND: Neurocognitively impaired patients with brain tumour are presumed to have reduced cognitive awareness preventing them from adequately valuing and reporting their own functioning, for instance, when providing patient-reported outcomes (PROs) such as health-related quality of life instruments. In this cross-sectional study, we aimed at assessing the concordance of neurocognitive complaints (NCCs) and objective neurocognitive functioning (NCF) as a measure of cognitive awareness. METHODS: NCF was assessed using an internationally accepted clinical trial battery. NCC was assessed using the cognitive functioning questionnaire from the Medical Outcome Study (MOS) and the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire cognitive functioning subscale. Patients were divided in cognitively impaired and unimpaired groups, based on their NCF performance. Pearson's correlation coefficients between NCF and NCCs were calculated. The same procedure was used to evaluate the correlation of NCF and QLQ-C30 CF subscale. RESULTS: Data from EORTC trials 26091 and 26101 were pooled into a data set of 546 patients. Twenty percent of patients could be characterised as unimpaired (109) and 80% as impaired (437). Impaired patients reported more cognitive complaints on the MOS scale than unimpaired patients. Correlations between NCF and NCCs were weak but significant for impaired patients and non-significant for unimpaired ones. Similar results were found for the correlation between NCF test performance and the QLQ-C30 CF subscale. CONCLUSION: Correlations between NCF test scores and complaints were weak but suggesting that neurocognitive impairment in patients with HGG does not preclude cognitive awareness. However, considering the findings of this study, we would suggest not to use PROs as a surrogate of performance-based neurocognitive evaluation.