OBJECTIVE: To estimate the efficacy and safety of original memantine and generic medication (memantal) in patients with mild/ moderate dementia due to Alzheimer’s disease (AD). MATERIAL AND METHODS: A six-month randomized controlled comparative study included 50 patients with mild/moderate dementia due to AD. Patients were naive to memantine and IAChe. Original memantine and generic medication dosage (5 mg daily) was titrated according to the manufacturer's recommendations. Patient’s condition was assessed with MMSE, the Neuropsychiatric Inventory (NPI) and IADL. Side-effects were recorded. RESULTS: There were no statistically significant differences in cognitive functions, neuropsychiatric symptoms, instrumental activity and safety between original memantine and generic medication. Both medications slightly improved patient's cognitive functioning, mostly in patients with mild dementia due to senile type of AD. CONCLUSION: The generic medication (memantal) and original memantine have equal efficacy and safety in patients with mild/moderate dementia due to AD.