Abstract: The widespread adoption of VLSI devices for safety-critical applications asks for effective tools for the evaluation and validation of their reliability. Fault Injection is commonly adopted for this task, and the effectiveness of the adopted techniques is therefore a key factor for the reliability of the final products. In this paper we present new techniques for exploiting FPGAs to speed-up Fault Injection in VLSI circuits. Thanks to the suitable circuitry added to the original circuit, transient faults affecting memory elements in the circuit can be considered. The proposed approach allows performing Fault Injection campaigns that are comparable to those performed with hardware-based techniques in terms of speed, but shows a much higher flexibility in terms of supported fault models.