The agricultural sector has been identified as the largest contributor to non-point source pollution (NPSP) of surface and ground water. Agroforestry, a land management practice that intersperses agricultural crops with trees, recently received attention in the temperate zone due to its environmental and economic benefits. A paired watershed study consisting of agroforestry, contour strip and control treatments with a corn (Zea mays L.-soybean [(Glycine max (L.)Merr.] rotation was used to examine treatment effects on runoff, sediment and nutrient losses. In 1991 watersheds were established and instrumented with H-flumes, and runoff was measured with ISCO bubbler flow meters. Runoff samples were collected using ISCO samplers and composite samples were analyzed for sediment and nutrient concentrations. Agroforestry and contour grass buffers were established in 1997. Relationships developed for runoff, sediment, and nutrients during the calibration period were used to examine influences of agroforestry and grass buffer effects on NPSP reduction. In both treatments, most runoff reduction started to occur in the second and third year after treatment establishment. Between 2001 and 2004, the agroforestry and contour strip treatments reduced runoff by 16 and 18%, respectively. The agroforestry treatment reduced N and P loss by 21 and 20%, respectively. The reduction in N and P on the contour strip watershed were 20 and 24%, respectively. Results indicate that agroforestry and contour grass strip practices effectively reduce runoff, sediment and nutrient loss from corn-soybean watersheds. It is anticipated as trees grow and roots occupy more soil volume, the reduction in N and P in runoff should increase on the agroforestry watershed.