Ultrasound has been utilized to assist gene transfection. In combination with ultrasound, microbubble-based contrast agents have also been used to enhance the transfection efficiency by inducing acoustic inertial cavitation. However, the relations between inertial cavitation and gene transfection rate/cell viability are still unknown. It is the primary purpose of this study to examine the relations experimentally and quantitatively. A commercial contrast agent Levovist® was used, and the cavitation was represented by the parameter ICD (inertial cavitation dose). The relations between ICD and gene delivery rate/cell viability were studied under various acoustic pressures, microbubble concentrations and pulse durations. Concentration of cells (HeLa cells) and DNA (short DNA-FITC molecules) were 2×105 cells/mL and 40 μg/mL, respectively. Linear regression was performed on the delivery rate versus ICD and the cell viability versus ICD. For the delivery, y=28.67x+10.71 (x: ICD, y: delivery rate) was obtained (R2=0.95). On the other hand, y=-62.83x+91.18 (x: ICD, y: cell viability) was obtained (R 2=0.84) for cell viability. The results show high correlations between delivery rate/cell viability and ICD.