While there is general agreement that the great majority of offenders who are sentenced to prison live with a mental disorder and/or a neurocognitive impairment, there is a paucity of research that examines the impact of these conditions on sentencing decisions. This article analyses three studies that reviewed Canadian sentencing decisions obtained from legal databases. Specifically, the article examines the extent to which neurocognitive impairment was treated as a mitigating factor. The analysis indicates that psychopathy was considered to be an aggravating factor insofar as it was associated with a lengthy or indeterminate prison sentence. FASD was consistently considered a mitigating factor with respect to young offenders but, for adult offenders, the judicial approach was variable with less concern for a specific diagnosis and treatment. In a small number of adult cases, PTSD was explicitly identified as a mitigating factor in the judgments, but only if it was causally connected to the offence(s). However, in cases involving young offenders, judges were more likely to focus on the need for treatment of this condition and speedy intervention to achieve rehabilitation. ADHD was not given much weight in sentencing decisions involving either young or adult offenders.