Intrusive errors in verbal memory tests could be considered as a preclinical marker of familial Alzheimer disease (AD). AIMS. To analyze and to compare the number and types of intrusive errors in the CERAD verbal memory test, administered to a genealogy of affected by familial AD, with E280A presenilin-1 mutation.Sample was constituted by 30 asymptomatic non-carriers (ANC), 39 non-demented carriers (NDC) and 21 demented carriers (DC). CERAD verbal memory test was administered to the sample. Comparisons, with non parametric Kruskal-Wallis' analysis, were done.NDC participants presented more intrusive errors than ANC group in the first and second trials and in the delay recall of the memory task; also they had more intrusive errors than the DC patients in intrusive errors of the first trial and delay recall of the same task. The ANC and DC groups had significantly more intrusions only in third trial.Intrusive errors could be considered as a cognitive preclinical marker for familial AD.