A new method based on image analysis for electrospun nano fibre diameter measurement is presented. First, the SEM micrograph of the nano fibre web obtained by electrospinning process is converted to binary image using local thresholding method. In the next step, skeleton and distance transformed image are generated. Then, the intersection points which bring about untrue measurements are identified and removed from the skeleton. Finally, the resulting skeleton and distance transformed image are used to determine fibre diameter. The method is evaluated by a simulated image with known characteristics generated by ?- randomness procedure. The results indicate that this approach is successful in making fast, accurate automated measurements of electrospun fibre diameters.