In this study, the vertically-integrated total column water vapor (TCWV) generated from four popular meteorological reanalysis data, including NCEP-R2, CFSR, ERA-40 and ERA-interim, were compared against the SSM/I TCWV, with a focus on spatial distribution and temporal variation patterns. The analyses showed that the TCWV from ERA-40 bears strong resemblance to that from SSM/I in both spatial distribution and temporal variation patterns. This result seems to be in contradiction to what we have anticipated, i.e., the third generation reanalysis products are not necessarily superior to the previous ones, which is a noteworthy caveat for the climate research community. This study simply compares the differences among various reanalysis data; while the underlying causes responsible for such differences are not discussed as those are beyond the scope of this study.