Low frequency noise (LFN) is important in analog and digital circuits. In analog circuits it affects the performance of low-noise amplifiers and the phase noise (1) of voltage-controlled oscillators (2). In digital circuits it becomes more important as the supply voltage is reduced and it degrades substrate noise coupling. Low-frequency noise is due to interactions of the channel carriers with oxide/semiconductor interface traps and oxide charges and is very dependent on the quality of the oxide/semiconductor interface and noise measurements can give important information about such interfaces and defects (3). Silicon-on-insulator devices have two oxide/semiconductor interfaces and the bottom interface is generally worse than the top interface. Most LFN measurements are made after MOSFET fabrication, but it is desirable to characterize such materials without fabricating devices. In this paper we discuss silicon-on-insulator (SOI) low-frequency noise and interface trap density measurements using a Ground-Signal-Ground (GSG) pseudo-MOSFET structure with minimum fabrication. Copyright The Electrochemical Society.