OBJECTIVE.- To determine persistence of treatment with donepezil (DON), rivastigmine (RIV), galantamine (GAL) and memantine (MEM) in patients with Alzheimer Dementia (AD) in a Spanish population setting. METHODS.- Retrospective AD cohort study performed in nine Primary Care Health Centers from four different Autonomous Communities (Andalucia, Cantabria, Cataluña & Valencia) in Spain. Descriptive standard analyses were performed. ANOVA and Chi-square tests were used to show the differences among mean duration therapy and treatment adherence after 52 weeks. A Kaplan-Meier survival analysis was applied to assess overall pattern persistence after three-year of follow up, and the log rank test was used for testing significance. RESULTS.- A total of 299 patients (44.8% female), mean age 77.88 years (SD: 6.32), were included; 101 DON (34%), 105 RIV (35%), 51 GAL (17%) and 42 MEM (14%). Mean treatment duration was slightly longer and significant for DON patients 83.3 weeks (95% CI: 72.7-93.9) than for the other drugs: RIV; 76.6 (66.0-87.3), GAL; 65.8 (55.3-76.3), MEM; 60.9 (48.8-73.1), p=0.049. Treatment adherence after 52 weeks was numerically higher with DON (63%) than with the other medications: RIV; 55%, GAL; 55%, and MEM; 52%, p=0.525. Overall persistence of treatment was significantly higher with DON [median time; 70.3 weeks (95% CI: 49.8- 90.7)] than for the others drugs: RIV [56.1 weeks (36.1-76.2)], GAL [56.7 weeks (41.1-72.3)] and MEM [52.1 weeks (35.2-69.1)], Log Rank=10.16, p=0.017. CONCLUSION.- This retrospective study including Spanish AD patients showed numerically differences on treatment adherence after one year of therapy among the four antidementia medications commercially available. The global treatment persistence during the three-year follow up was significantly higher in patients treated with donepezil compared to those who received rivastigmine, galantamine or memantine.