We showed that the propensity score weighted M-estimation method proposed by Hoshino (2005) can be applied in order to adjust for the bias in sampling surveys for marketing research. Further, using real data sets, we investigated the capabilities and the limitations of the propensity score adjustment method to the adjustment of the biased internet surveys and demonstrated the validity of Hoshino's method. By using the covariates selected the method proposed by Hoshino and Maeda (2006) in two similar surveys, we found that the effectiveness of the adjustment method using the propensity scores was reproducible.