The objective of this paper is to present an Automated Geometric defect Diagnosis methodology for EEPROM cell (AGDE). This method focuses on speeding up the diagnosis process of geometric defect.It is based on a mathematical model generated with a "Design Of Simulation" (DOS) technique. The DOS technique takes as input, simulations results of a floating gate transistor with different given geometries and produces, as output, a polynomial equation of the threshold voltage in function of the cell?s geometric parameters. The diagnosis process is realized in comparing the measured threshold voltages of an EEPROM cell with the dynamically computed ones. From this comparison, the potentially defective geometric parameters are automatically extracted.