Despite the development of multiple cranial bone substitutes, calvarial reconstruction remains a significant challenge. Although autologous bone is preferred in many cases, its usefulness may be limited by difficulty with contouring, resorption, and donor site availability and morbidity. Alloplastic cranioplasties are also widely used with each material having its advantages and disadvantages. Computer-designed implants have the advantages of minimizing operative time for preparation, shaping, and insetting. We report our initial clinical experience in 6 patients with computer-designed, prefabricated polyetheretherketone implants, which may have significant advantages over other alloplastic materials in terms of strength, stiffness, durability, thermal conductivity, and radiographic translucency.