Despite the many studies examining linguistic deterioration in Alzheimer's disease (AD), very little is known about changes in verbal expression during the preclinical phase of this disease. The objective of this study was to determine whether changes in verbal expression occur in the preclinical phase of AD. The sample consisted of 40 healthy Spanish speakers from Antioquia, Colombia. A total of 19 were carriers of the E280A mutation in the Presenilin 1 gene, and 21 were noncarrier family members. The two groups were similar in age and education. All the participants were shown the Cookie Theft Picture Card from the Boston Diagnostic Aphasia Examination and were asked to describe the scene. Specific grammatical and semantic variables were evaluated. The performance of each group was compared using multivariate analyses of the variance for semantic and grammatical variables, and errors. Carriers of the mutation produced fewer semantic categories than noncarriers. In the preclinical phase of AD, changes in verbal expression are apparent and early detection of these differences may assist the early diagnosis of and intervention in this disease. (JINS, 2007, 13, 433–439.)