Based on NOAA/AVHRR NDVI biweekly time-series data, the start and end of the growing season of Central Asia from 1982 to 2006 were estimated. Trend analysis results indicate an earlier green-up and a later dormancy over the entire area during the study period. For seven main vegetation types, the largest advance of greenup onset (0.597 days/year) occurs in cropland and the longest delay of dormancy (1.109 days/year) in open shrubland. The smallest advance (0.164 days/year) occurs in evergreen needleleaf forest and delay (0.443 days/year) in crop/natural vegetation mosaic. These results imply enhanced vegetation activity in the Central Asia region over last decades.