Alzheimer’s disease (AD) is a progressive neurological disease of the brain leading to the irreversible loss of neurons and intellectual abilities. Diabetes mellitus type 2 (T2DM) is a metabolic disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. The prevalence of AD and T2DM is increasing at an alarming rate and has become a major public health concern worldwide. The clinico-pathological relationship between AD and T2DM has been debated for more than a decade. Recent epidemiological studies have provided direct evidence that T2DM is a strong risk factor for AD and numerous studies have demonstrated that patients with diabetes have an increased risk of developing AD as compared with healthy individuals. The underlying biological mechanisms that link the development of diabetes with AD are not fully understood and therefore are worth intensive research. The existence of proteomic links between AD and diabetes is an important topic currently under active debate. An understanding of the complex association between diabetes and AD is necessary for the development of novel drug therapies and lifestyle guidelines aimed at the treatment and/or prevention of these diseases. This review aims to summarize what is currently known about the biological and especially proteomic relationships and similarities between these two age-related devastating diseases of modern day life. This study may also aid in future for the identification of a single or a panel of potential blood-based protein biomarkers for early diagnosis of AD and T2DM with high sensitivity and specificity.