Building on the e-Satisfaction model proposed by Szymanski and Hise (2000) and further validated by Evanschitzky, Iyer, Hesse, and Ahlert (2004), we develop an instrument to measure shopper satisfaction in online and offline retail contexts: the (R)E-Tail Satisfaction scale. Using data from an online (N=202) and an offline (N=441) grocery shopper sample, the instrument is shown to be fit for cross-channel evaluation of levels of satisfaction and its antecedents. We find full metric invariance (identical factor loadings), sufficient partial scalar invariance (identical item intercepts for at least two items per construct), as well as some interesting structural differences. Most notably, online shoppers evaluate the facets of retail satisfaction generally lower than do offline shoppers.