Changes in Earth's polar ice sheets affect global energy/water cycle and is a strong indicator of global climate change. One important component in the polar water/ice balance is the atmospheric moisture transported from the ocean in lower latitudes, which is traditionally estimated from rawinsonde measurements. We developed a method to estimate vertically integrated moisture transport (IMT) over oceans using spacebased scatterometer and microwave radiometer observations. Preliminary analysis of IMT in polar region has demonstrated credible annual and interannual variations of moisture transport into Antarctica, and revealed the correlation between recent Greenland ice-sheet melting and hydrologic balance. We will present the technique on estimating IMT based on satellite data, taking advantage of ocean surface vector wind fields with unprecedented coverage and resolution by NASA scatterometer SeaWinds on QuikSCAT. We will relate quantitatively the moisture transport into Greenland and Antarctica to the change in snow/ice accumulation and sea ice extent observed by spaceborne instruments and local stations.