During the last years, GFR estimation has received substantial attention with a focus on comparing results of new formulas with GFR measurements, and standardization of creatinine assays. Calibration of creatinine should improve performances. However, frequently used equations have lower precision in high GFR populations. This is the reason why a continuous effort in improving predicting equations is still needed. The use of calibrated creatinine, the onset of new GFR markers such as cystatin C, and pooling data across many study populations are underway to develop better prediction.