The authors carried out a double-blind study in two randomized homogeneous groups of both sexes of 15 patients each, over 65 years of age and suffering from mild mental impairment. One group of patients underwent therapy with acetyl-L-carnitine, 2 g/day for three months, while the other group was treated with a placebo. The statistical evaluation of the results were carried out using nonparametric methods (Friedman-Nemenyi two-way Anova and Mann Whitney U-Test). However, the two groups did not differ significantly in either test at the end of treatment. It is possible to affirm that the acetyl-L-carnitine treated patients showed statistically significant improvement in the behavioural performances (Blessed Dementia Scale p less than 0.02; Stuard Hospital Geriatric Rating Scale p less than 0.01), in the memory tests (Rey short-term p less than 0.02; Rey long-term p less than 0.05; Corsi p less than 0.05), in the attention test (Barrage test p less than 0.01) and in the Verbal Fluency test p less than 0.01).