The aging process occurs gradually, is highly individual, with a high degree of inter and intra-individual differences. As such, within an aging population there is significant variation in regards to extent of age related disease and functional impairment. This variability between individuals is thought to be expressed as biological age. Currently, the comprehensive geriatric assessment (CGA), a multidimensional, interdisciplinary diagnostic process is used to determine an individual's medical, psychological and functional capability at older age. However, while the CGA utilises well-established markers of physical and functional parameters, it does not include any molecular measures that indicate an individual's biological age. Combining functional measures with molecular markers of biological age, could improve the current CGA by identifying individuals undergoing a rapid aging process. In this review, the current knowledge and clinical utility of potential biomarkers of aging are presented. Although no biomarkers indicative of biological age are currently being utilized in the clinical setting promising research advancements would suggest their application in the near future.