An accurate assessment of renal function is crucial for the diagnosis and follow up of kidney diseases. However, there is currently no clear consensus on the optimal method on how to measure renal function in older individuals (>65 years of age). The Cockcroft-Gault formula, the MDRD equation, and the CKD-EPI equation are among the most used equations. However, they have several limitations when applied to the older population. Other formulas specifically developed for the older, such as the Berlin Initiative Study (BIS) and the Full Age Spectrum (FAS) equation, demonstrated conflicting results and require more external validation. This article provides an overview of the currently available methods to assess renal function in the older persons and summarizes their shortcomings.