PharmaCOG is an industry-academic European project aimed at identifying reliable biomarkers that are sensitive to disease progression in patients with mild cognitive impairment. Several automated methods for quantitative assessment of white matter hyperintensities (WMH) have been recently developed (for a review see Caligiuri, 2015). However, the longitudinal reproducibility of these approaches has been poorly investigated. Here we present preliminary work aimed at evaluating the across-session test-retest reproducibility of the automated WMH quantification computed with SPM12 (Schmidt, 2012) on a group of healthy elderly subjects. Eleven 3T MRI sites (Siemens, GE, Philips) participated across Italy, Spain, France, Germany, Greece and The Netherlands. The acquisition protocol includes one 2D FLAIR sequence: acceleration factor in the range of 1.5 to 2 where possible (GRAPPA, SENSE and ASSET in Siemens, Philips and GE systems, respectively), 0.9x0.9x4mm3, with TE/TR/TI as recommended by the ADNI project (Jack, 2008). Five local healthy volunteers (55–90 years) per site were scanned in two sessions a week apart. The segmentation of WMH was performed using lesion segmentation tool (LST) version 2.0.15 (Schmidt, 2012) with optimized parameters and applying the longitudinal correction. The WMH volume and number of lesions reliability for each subject was computed evaluating test-retest absolute differences relative to the mean. Visual assessment indicates good segmentation results. The WMH volume was comparable across sites (Kruskal–Wallis, p=.143) and was around 1.6 ml (SD=2.9). The reproducibility error of total WMH volume averaged across sites was 2.3% (SD= 7.0) while that reported for the lesion number was 1.9% (SD=7.0). None of the WMH volume reproducibility metrics showed MRI site effects (Kruskall-Wallis test, p>.185). Despite the differences of MRI scanner configurations across our 11 sites we found consistent WMH volumes and lesion count reliability. Our findings suggest that the WMH volume may be a reliable longitudinal marker in multisite studies. Pharmacog is funded by the EU-FP7 for the Innovative Medicine Initiative (grant n°115009).