As part of the U.S. Department of Energy's Wind Partnerships for Advanced Component Technologies (WindPACT) Program, a scaling study was performed oil composite wind turbine blades. The study's objectives were to assess the scaling of current commercial blade materials and manufacturing technologies for rotors of 80 to 120 meters in diameter, to develop scaling curves of estimated weight and cost for rotor blades in that size range, and to identify practical limitations to the scaling of current conventional blade manufacturing and materials. Aerodynamic and structural calculations were performed for a matrix of baseline blade design parameters, and the results were used as a basis for constructing a computational scaling model. The scaling model was then used to calculate structural properties for a wide range of aerodynamic designs and rotor sizes. Blade designs were evaluated oil the basis of power performance, weight, static strength in flapwise bending, fatigue life in edgewise bending, and tip deflection under design loads. Calculated results were compared with weight data for current commercial blades, and limitations were identified for scaling lip the baseline blade configurations. A series of parametric analyses was performed to quantify the weight reductions possible by modifying the baseline design and to identify the practical limits of those modifications. The model results provide insight into the competing design considerations involved in scaling up current commercial blade designs.