An efficient design and VLSI implementation of a high data rate Medical Implant Communications Service (MICS) digital baseband transmitter for implantable medical devices is proposed in this paper. An orthogonal frequency division multiplexing (OFDM)-based multicarrier scheme is used to overcome the data rate limitation caused by the narrow bandwidth of 300 kHz. The proposed transmitter can support enhanced data rate by utilizing multiple channels simultaneously. Furthermore, to satisfy the MICS regulation, various schemes are applied including optimized subcarrier allocation for inverse fast Fourier transform (IFFT) and additional sidelobe suppression technique. The proposed transmitter with optimized hardware architecture is verified by VLSI implementation and it can support a maximum data rate of 4.86 Mbps, which is more than ten times faster than the previous systems.