Brain metastases are a frequent complication of many cancers. Whole brain irradiation is the main treatment of these. However, improvements of therapeutical efficiency increased life expectancy of patients with brain metastases. Consequences of whole brain irradiation include neurocognitive degradation, but this remains poorly evaluated. Recently, using of battery of neuropsychological tests led to question the dogma of the ineluctable brain toxicity of the radiotherapy. Analysis of the literature allows concluding that the first cause of deterioration of neurocognitive function after brain irradiation is the lack of brain disease control.