When subjected to MRI and its radio frequency (RF) field, metallic leads of an implanted electronic device such as a pacemaker may behave as antennae. The induced current surrounding the electrodes may heat the local tissue [1]. The MRI-induced tissue heating around the electrodes of a pacemaker have only been investigated for pacemakers employing a single lead [2], [3]. In this paper, we examine the MRI-induced temperature rise (TR) of the tip electrode(s) associated with a pacemaker system with two St. Jude Medical Tendril 2088 STS leads.Due to the complex and tiny pacemaker leads structure, it has an established transfer function (TF) modeling the conversion of the incident electric field to an induced current which may be employed in analyzing the electrode/tissue heating effect [4]. The tip TR can be estimated by squaring the inner product of the incident electrical field along the lead pathway and the TF. Consequently, the lead heating impact of adding a second lead to a pacemaker system can be estimated by comparing the TFs of pacemaker systems with 1 V.S. 2 leads. We measured the TFs using established means [2], [3] of 1 and 2-lead pacemaker systems in a saline bath phantom with electrical conductivity of 1.2 S/m and a relative permittivity of 80 at 64 MHz, approximating the electrical characteristics of blood. TR measurements were performed with leads located along several phase reversal pathways in the ELIT1.5 phantom filled with HEC gel with the same electrical parameters as the saline used in the TF measurement. The two leads are separated at 3cm from distal end to avoid the interference to the local SAR (Specific Absorption Rate) distribution from each other. The phantom was loaded in the MITS 1.5 T vertical RF coil as show in Figure 1.The TF of a pacemaker system with two Tendril 2088 58cm STS leads was measured, scaled and compared with that of a system with a single lead. The magnitude of the two lead TF was clearly lower than that of the single lead, and the shape was also changed, as show in Figure 2 (a); meanwhile, the TF phase of the dual lead system was almost identical to that of the single lead system, as shown in Figure 2 (b). Based on the TF value, a much lower TR would be expected for the dual lead system, which was verified by the in vitro measurement result as shown in Figure 3. The triangle marks and the circular marks represent the measured TR from a single lead and dual leads, respectively. On average, a 47% drop in TR was achieved with the dual lead system. However, this heating from the dual lead pacemaker system cannot be directly predicted by scaling the single lead result because the transfer function shape was also changed. A careful TF validation process was accomplished by comparing the predicted and measured TR on each lead pathway as shown in Figure 4.We compared the MRI-induced lead heating resulting from pacemaker systems employing one and two leads. The dual lead system experienced significantly reduced tip heating compared to the single lead system. We have shown that the RF heating TF methodology specified in ISO/TS 10974 can be extended to dual lead TF and that the accuracy of dual lead TFs are comparable to single lead TFs.