Electrospinning process was optimized by using response surface methodology (RSM) to fabricate MWCNTs/PAN nanofibril composite non-woven fabrics of 180 nm average fiber diameter. The as-electrospun fabrics were hot-pressed to produce strong and flexible carbon nanofibril composite papers of 130 nm average fibril composite diameter. Dielectric constant of 300 and conductivity of 310 S/m were measured for these papers by using H10K13532-50LCR meter at 25,000 Hz. Analytical approach was introduced based on Lichtenecker modification formula to evaluate the electrical properties of the embedded MWCNTs, single nanofibers and single nanofibril composites as function in fabrics measured properties. 4156 S/m for MWCNTs, 360 S/m for carbonized electrospun PAN single nanofibers and 517 S/m for carbonized electrospun 5 wt% MWCNTs/PAN single nanofibril composites were reported. The ability to control the electrical properties of these papers over a wide range should position them as a versatile advanced material for numerous electronic, sensors and inter-connect applications. (C) 2014 Elsevier B.V. All rights reserved.