Presented at the 2013 Aquarius/SAC-D Science Team MeetingTo date, both AQ and SMOS missions have observed significant differences between L-band SSS retrievals in the presence of rain and surface truth (buoys and HYCOM model). Based upon pre-launch analyses of rain effects, this is an unexpected result, which begs the question "Is it retrieval error or science?" In an attempt to resolve this issue, an AQ Rain Accumulation product has been developed to overlap the Aquarius L2-SSS data. It is derived from the Tropical Rainfall Measuring Mission (TRMM) 3B42 product, which is a near-global, gridded rain rate dataset that extends from ±50° latitude and is produced 8 times daily at 0Z, 3Z, 6Z . . . and 21Z (3-hr windows). Based upon the AQ pixel observation time, these 3B42 data are temporally interpolated in 3-hr windows and spatially averaged over each AQ IFOV to produce a rainfall history during the previous 24hrs. The purpose of this paper is to describe this AQ Rain Accumulation product and to present validation results using independent WindSat rain retrievals (EDR) that occur within ±45 minutes for ~60% of the AQ L2 science data pixels.