R2* mapping has the potential to provide rapid and reliable quantification of liver iron concentration. Importantly, previous studies have demonstrated that by correcting for relevant confounding factors (eg: noise floor effects and fat) R2* mapping is highly insensitive to the presence of these confounders. However, the repeatability and reproducibility of confounder-corrected R2* across multiple sites and vendors remains unknown. This abstract reports interim results from a multi-center, prospective, NIH-sponsored liver iron quantification study. Our results suggest excellent repeatability and reproducibility of confounder-corrected R2* for liver iron quantification in patients, across four centers, three vendors and at both 1.5T and 3T.