Nitrogen movement and transformations were studied within two contrasting watersheds in the Green Mountains of Vermont. Nitrate export patterns and pH (pH 4.8 vs. 6.8) differed between two tributaries of Brush Brook draining areas containg soils with similar chemistry. Although the nitrate export patterns in the two streams had distinct differences, and potentially a different nitrate source, the d 15N and d 18O of nitrate in both streams showed minor differences, regardless of the time of year. Streamwater nitrate, even during snowmelt, is more isotopically similar to soil nitrate than precipitation indicating that streamwater nitrate has a microbial origin.