Most of the antennas that are implanted into the human body are widely used for biotelemetry and hyperthermia purposes. In this paper, a miniaturized microstrip implantable patch antenna design is introduced which is used for Medical Implant Communications Service (MICS, 402–405 MHz) band biomedical applications. Since MICS band antennas operate in low frequency as compared to Industrial Scientific and Medical (ISM, 2.4–2.48 GHz) band and the size of the antenna is comparably large, miniaturization techniques are used to reduce the physical size of purposed antenna. A shorting pin and four ground slots are used for miniaturization purpose of antenna. The purposed miniaturized implantable antenna has two rectangle patches and one square shape outer ring element, in which all elements are electrically connected by metallic pad with a total dimension of 14 × 14 × 2.54 mm3. The proposed implantable patch antenna provides approximately 9.86% impedance bandwidth with improved dBi gain in the MICS band. Return loss characteristics, radiation pattern, bandwidth, and parametric study of some important parameters are analyzed of the purposed antenna.