Technical Abstract: Survey data from the Fort Cobb Reservoir watershed (FCRW) in southwestern Oklahoma were used to evaluate farm-level management practices for no-till and conventional tillage. The Farm-level Economic Model (FEM), an annual economic simulation model, was used to determine impacts of alternative tillage practices on farm profits under various diesel price and winter wheat yield scenarios. While the emphasis was on winter wheat, alternative tillage simulations were performed for all applicable crops grown in the area. Sensitivity analysis was performed using plausible ranges in diesel prices and in the effects of tillage practices on winter wheat grain yields. The results indicate that if winter wheat grain yields not impacted by tillage systems, no-till would be more profitable than conventional tillage or the current mix of tillage practices in the watershed. Even if the switch from conventional tillage to no-tillage resulted in a small yield penalty (about 5%), no-till would still be more profitable even at reasonably low diesel price levels. Only when there is a significant wheat yield penalty associated with no-till (10% or greater) might no-till be less profitable than conventional tillage or the status quo at reasonably high fuel prices. In general, for each 1% improvement in wheat yields under no-till relative to conventional tillage, no-till farm profits improve by $3/acre on farms that produce only winter wheat, and an average of $1/acre if averaged across all farms in the FCRW, including those that do not produce winter wheat. Similarly, for each $1/gallon increase in the price of diesel fuel, no-till farm profits improve by roughly $1/acre relative to conventional tillage.