<i>Background/Aims:</i> The diagnosis of mild or questionable Alzheimer’s disease (AD) depends on clinical criteria that often leave a margin for doubt. We aim to verify the diagnostic accuracy of amnestic mild cognitive impairment (aMCI) and AD with proton spectroscopy (¹H-MRS) combined with brief cognitive-functional scales. <i>Methods:</i> The relationship between ¹H-MRS of the posterior cingulate cortex and the cognitive performance in Mini Mental State Examination, Blessed-Roth Dementia Rating and Functional Assessment Staging of Alzheimer Disease scales were investigated in 25 AD, 10 aMCI and 33 normal control (NC) individuals. <i>Results:</i> The N-acetylaspartate (NAA)/creatine and myoinositol/NAA ratios distinguished AD patients from NC (p < 0.005), and added value in diagnostic accuracy and specificity by discriminant function analysis when combined to clinical diagnosis and simple neuropsychiatric scales; an increase of 3.7% (for aMCI patients) and of 5% (for AD individuals) was observed in diagnostic accuracy, and one of 5.5% (aMCI) and of 11.1% (AD) in specificity. <i>Conclusion:</i>¹H-MRS combined with brief cognitive-functional scales provided maximum diagnostic accuracy of AD patients, and can be useful when subtle cognitive and memory dysfunction is present.