Nanoscaled interdigitated electrodes (IDEs) were developed for the purpose Of being used as miniature and sensitive affinity biosensors. IDEs with palladium as the electrode material on a SiO2 substrate were made with electrode widths and spacings ranging from 550 nm down to 250 nm. These sensors were theoretically modeled, enabling the prediction of their impedimetric response in KCl solutions. The strength of the theoretical model was proven by a characterization of IDEs of various dimensions in KCl solutions of different concentrations. The results demonstrate a quite reproducible behavior and a correlation between the impedimetric response in KCl solutions and the electrode dimensions.