The neuropsychology of anosognosia for memory impairment in Alzheimer's disease (AD) was examined in 92 AD patients and 92 case matched individuals for comparison, using three quantitative methods of assessment: Experimenter Rating Scale (ERS), Objective Judgement Discrepancy (OJD) and Subjective-Rating Discrepancy (SRD). The OJD showed significant domain specific correlations with memory functioning as well as a significant correlation with susceptibility to intrusional errors. Memory or executive dysfunction may affect the immediate ability to judge cognitive performance in a domain specific manner (secondary anosognosia). Longer-term awareness of cognitive deficit appears less influenced by impaired basic cognitive functions, than by the decline of metacognitive function (primary anosognosia).