AbstractBackgroundImpaired semantic memory is one of the earliest characteristic features of Alzheimer’s disease. Its assessment is crucial to accurately predict conversion to Alzheimer disease related disorders (ADRD). Recent evidence supports the necessity to differentiate between subprocesses of semantic cognition: a) activation in the semantic representation system; b) executive processes to control or select relevant aspects of semantic knowledge. In this study we compare semantic memory tests that differ in these subprocesses to find out which of them are the best predictors of conversion of MCI to ACD in two years. We also want to identify which semantic memory tests have more sensitivity and specificity at the baseline in the differentiation MCI‐no converters and MCI converters after two yearsMethodWe assessed 130 amnestic MCI patients. Semantic memory tests more based on integrity of semantic knowledge (Similarities, ACE‐language) and more executive determined (verbal fluency – phonemic and categories, Boston Naming Test) were administered at baseline and at 2‐years follow‐up, together with cognitive screening tools and IADL measures. A binary regression model was used to examine which semantic memory tests predict MCI progression to Alzheimer’s Clinical Syndrome (ACS) in two years. ROC curves were used to study early clinical diagnosis differentiating MCI converters and MCI non convertersResultOnly semantic category fluency test significantly explained the conversion to ACS (p<.01). Baseline score semantic categories fluency were significantly lower in MCI patients who develop ACS after two years (p<.001). ROC curves showed that semantic categories fluency and Boston Naming tests were the best tests to differentiate at baseline between MCI converter and non‐converter (AUC = 0.768, p<0,0001 and AUC = 0.712, p<0,01, respectively)ConclusionSemantic category fluency test was the best predictor from MCI to ACS conversion in two years. Semantic category fluency and Boston Naming tests clearly identify people with high risk to develop ACS in two years. Semantic memory tests including executive contributions could detect and characterize prodromal Alzheimer’s disease