The paper addresses the issue of transistor-level bridging fault diagnosis. While most of the previous bridging fault diagnosis work focuses on the gate-level bridging faults, this method provides a solution to intragate bridging faults diagnosis for the first time. Instead of using any transistor level simulation tools, we develop a transformation technique that allows transistor-level bridging faults to be diagnosed by the commonly used gate-level bridging faults diagnosis tools. Real diagnosis results from Philips designs are presented.