AIM: To analyze the performance of verbal fluency tasks by elderly people with different types of cognitive impairment. CASE REPORT: The study included patients from Hospital de Clinicas de Porto Alegre (Porto Alegre, Brazil), who were older than 65 years and presented with probable Alzheimer's disease (PRAD), vascular dementia (VD), and mild cognitive impairment (MCI). The diagnostic criteria were based on those of the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA), National Institute of Neurological Disorders and Stroke and Association Internationale pour la Recherché et l'Enseignement en Neurosciences (NINDS-AIREN), and Petersen (1999). The study also included a healthy elderly group. All study participants provided informed consent. Patients were assessed for phonological fluency (PF) and semantic fluency (SF). RESULTS: Statistical analysis was performed using ANOVA and the Kruskal-Wallis test (0.05 was the significance level). All groups had 17 patients. The healthy elderly group showed mean SF and PF values of 12.69 and 26.37, respectively. The PRAD group showed mean SF and PF values of 6.40 and 14.50, respectively. The VD group showed mean SF and PF values of 6.00 and 24.00, respectively. The MCI group showed mean SF and PF values of 11.27 and 15.00, respectively. There was a significant difference between the groups in SF (p < 0.000) and in PF (p < 0.000). The PF differed significantly between each patient group and the group of healthy individuals. CONCLUSION: Elderly patients with cognitive impairment had worse performance in verbal fluency than healthy elderly people. The PF and SF seem to be associated differently with different cognitive impairments.