Mild cognitive impairment (MCI) represents clinically significant cognitive decline with preserved everyday functioning. Vast amount of studies have shown that patients with MCI have increased risk for development symptoms of dementia. The probability of slowing down symptoms of dementia is closely related with an early diagnosis and intervention. Therefore, correct and reliable diagnosis of MCI plays very important role for clinicians, patients and their care-givers in making important decisions in subsequent treatment. Neuropsychological assessment aims to address question regarding level and type of cognitive decline. In the MCI literature we can find large amount of studies where neuropsychological data have been combined with other examinations (e.g. CSF, MRI, EEG). These studies have usually addressed question which combination of biomarkers are optimal in predicting individual progress to dementia. The aim of neuropsychological part of our study was (i) to find the neuropsychological measurements which are the best in predicting conversion from MCI to dementia, (ii) to separate different MCI subgroups by means of calculating robust memory and non-memory components, (iii) to combine the most predictive neuropsychological variables with other examinations and (iv) to address the question how are neuropsychological scores in MCI patients related to different modes of cognitive control. We recruited 80 participants (20 controls, 20 MCI, 20 Parkinson’s disease (PB), and 20 PB with MCI) to obtain the information about their cognitive functions.