A novel interface characterization technique is proposed to extract interface trap density Nit in fully depleted silicon-on-insulator MOSFETs. The proposed technique utilizes the temporal variation of the drain current, which is caused by the application of a single pulse to the gate in order to trigger charge pumping (CP). Vacant interface traps created as a result of recombination through the CP effect are gradually filled by carriers generated from a floating body (FB). By the characterization of this transient phenomenon, the interface trap density is directly extracted from FB devices without extra body contacts.