© 2020 University of Ankara. All rights reserved.Objective: The increase in elderly population due to the increasing population worldwide has led to an increase in the prevalance of Alzheimer’s disease (AD). In the last years, scientific studies on different types of dementia and particularly on AD have accelerated. It is known that this disease has multi-genetic grounds. However, exposure to several biological agents are also suggested to play roles in the pathophysiology of AD. There are studies in literature suggesting that infections like Herpes simplex virus tip-1 (HSV-1), human immunodeficiency virus type 1 (HIV-1), Helicobacter pylori and endogenous prion poteins can contribute to the development of this disease. On the other hand, there are studies suggesting that diseases like diabetes can expedite the development of AD. In this review, we aimed to focus on the the general properties of AD and will also mention the biological agents that are suggested to play roles in the pathophysiology of AD and the studies performed on these agents. Result and Discussion: Other than genetic factors, several biological agents may play roles in the emerging of AH. AH’nin ortaya çıkmasında genetik faktörlerin yanı sıra, birçok biyolojik ajanın rolü olabileceği belirtilebilir. Comprehensive and mechanistic studies are needed on this subject.