We report the results of a joint analysis of NDVI data derived from NOAA-AVHRR and snow parameters (snow depth and snowmelt timing) derived from satellite passive microwave measurements over Central Siberia. We investigate the influence of interannual variability in snowmelt and snow depth on vegetation activity from 1989 to 2000. In addition to the effects of temperature and precipitation, we observe significant correlations between the snow parameters and the NDVI. Later snowmelt dates and thicker winter snowpacks are related to higher NDVI values over a large latitudinal band at about 65¿N. This may be explained by either increased water availability for plants after snowmelt or thermal insulation of soil by snow. These results reflect the importance of snow-related winter processes on the vegetation development and on the carbon cycle in boreal regions.