We tested the efficacy and tolerability of one-year treatment with memantine (10 mg bid) in behavioral variant frontotemporal dementia (bvFTD). BvFTD patients aged 45 to 75 years, with a Mini-Mental Status Examination (MMSE) score ≥19, were enrolled in a national, randomized, double-blind, placebo-controlled (DBPC), Phase II trial. The primary endpoint was the CIBIC–Plus (Clinician's Interview-Based Impression of Change Plus Caregiver Input). The secondary endpoints included: Neuropsychiatric Inventory (NPI), Frontal Behavioral Inventory (FBI), Mattis Dementia Rating Scale (MDRS), MMSE, Disability Assessment for Dementia (DAD), and the Zarit Burden Inventory (ZBI). Forty-nine patients were analyzed. At baseline, mean age was 65.6 years and mean MMSE was 25.0 (range: 19–30). On the CIBIC–Plus, 52 weeks after baseline, there were no significant differences between the memantine group (n = 23) and the placebo group (n = 26); p = 0.4458; however, 10 patients had worsened in the memantine group versus 17 in the placebo group. For the secondary endpoints there were no differences in the evolution of score between the memantine group and the placebo group (MMSE, p = 0.63); (MDRS, p = 0.95); (NPI, p = 0.25); (ZBI, p = 0.43); (DAD, p = 0.10) except for the FBI score, which was lower in the memantine group (p = 0.0417). Memantine was well-tolerated. This is the first DBPC trial in a large group of bvFTD patients involving neuroprotective treatment. A multinational study with a larger number of patients is now needed in order to verify the results of our study. The trial is registered with ClinicalTrials.gov; number NCT 00200538.