Neural stem cells exist in the adult mammalian brain throughout life. They reside in the subgranular layer of the dentate gyrus and in the subventricular zone. Neural stem cells have the capability to self-renew, proliferate and differentiate into neurons and glia. The existence of neurogenesis permits high level of brain plasticity and provides a source for cellular replacement. Importantly, new neurons play a role in hippocampus-dependent learning and memory. Thus, modulation of neurogenesis has a high therapeutic value, once the molecular signaling regulating these processes is unraveled. This might be particularly critical for aging-linked cognitive decline, such as occurs in Alzheimers disease. Neurogenesis is impaired early in life in Alzheimers mouse models, and major players in Alzheimers disease regulate neural progenitor cell proliferation and differentiation. This lecture will discuss the molecular link between neurogenesis and Alzheimers disease and the ways by which impairments in neurogeneis may contribute to or exacerbate the disease. Finally, we will discuss neurogenesis-based therapy for the amelioration or attenuation of Alzheimers disease.