Quantitative susceptibility mapping (QSM) is a new technique, and it has been shown that results can vary according to the MRI device, phase reconstruction, and susceptibility estimation algorithms. Porting this mapping on the clinical practice would be of interest in numerous kind of pathology. However, it requires a validation which should be performed using a dedicated MR phantom. We described an easy to build MR susceptibility phantom based on iron sucrose. Using optimal parameters, the quantitative susceptibility mapping provides a very good estimation of the iron concentrations in the phantom.