With the prospect of potential treatments for Huntington's disease (HD), non-invasive markers of disease progression are needed. Cognitive impairment has long been recognised as one of the core symptoms of HD. The first aim of this review is to provide insight into the onset and nature of cognitive loss in the progressing stages of HD. The second aim is to provide an overview of the cognitive functions that have been examined in an attempt to identify those areas that have the most potential to yield a cognitive biomarker. Literature, consisting of 110 studies, since the implementation of genetic testing until the beginning of 2011 has been included in this review. The clinical features of premanifest HD include deficits in psychomotor speed, negative emotion recognition and to some extent in executive functioning. The clinical profile of manifest HD includes impairment in memory, psychomotor speed, negative emotion recognition and executive functioning. Furthermore, potential candidate biomarkers should be most expected from such domains as working memory, psychomotor speed, recognition of negative emotions, attentional and visuospatial executive functions.