Alzheimer’s disease is a progressive incurable neurodegenerative disease manifested by dementia and other cognitive disorders. Gene-cell therapy is one of the most promising trends in the development of treatment for Alzheimer’s disease. The study was aimed to evaluate the therapeutic potential of intravenous transplantation of human umbilical cord blood mononuclear cells (UCBMCs) transduced with adenoviral vectors overexpressing nerve growth factor (NGF) for the treatment of Alzheimer’s disease in an APP/PS1 transgenic mice model. The transplantation of NGF-expressing UCBMCs was found to improve spatial memory and decrease anxiety in APP/PS1 mice. Grafted cells and their expression of NGF were detected in the cortex and hippocampus of transgenic mice in the period up to 90 days after transplantation. Thus, gene-cell therapy based on the use of NGF-overexpressing UCBMCs is a promising approach for the development of Alzheimer’s disease treatments.