High performance polymer nanocomposites based on poly(etheretherketone) (PEEK) as matrix and modified clay as reinforcement were fabricated using hot pressing at 380 °C and 45 MPa. The clay was varied from 0 to 5 wt%. Nanocomposites were characterized by X-ray diffraction (XRD), Vickers hardness tester, high resistivity meter, and impedance analyzer to get information about morphology, microhardness, electrical conductivity and dielectric properties of nanocomposites, respectively. The experimental density was very close to the theoretical density. XRD showed exfoliation of clay up to 3 wt% and intercalation for 5 wt% nanocomposite. The water absorption decreased by 38 % at 1 wt% clay content. The microhardness increased up to 12 % for 2 wt% clay nanocomposite. Electrical conductivity was increased two orders of magnitude higher than pure PEEK. Dielectric constant was increased slightly with increasing clay content. The significant improvement in properties at lower clay loading might be attributed to the exfoliation of clay in the matrix.