The effect of transmit frequency on the risk of RF heating for elongated metallic implants was investigated through simulations in a phantom and a human model for 21, 64, 128 and 300 MHz. We demonstrate that for uniform E-field exposure, worst-case E-field enhancement at the tip reduces with increasing transmit frequency. However, for realistic E-field exposures, E-field enhancement increases with transmit frequency for similar B1+ levels. For similar head SAR levels, E-field enhancement for worst-case implant length is roughly equal for all transmit frequencies. In all cases implant length is the main determinant of RF heating.