Recently, micro- and nano-technologies have enabled rapid progress in biomedical applications. Although in vitro analytical and diagnostic tools have been the focus of such technologies, in vivo therapeutic and sensing applications have received significant attention in the past few years. Novel implantable drug delivery devices, which can precisely control key therapy parameters, have the potential to increase the efficacy of drug therapy. This paper presents an implantable CMOS drug delivery SoC, in which a wireless controller/actuation circuitry and a drug delivery array are monolithically integrated. Compared with current technologies, the advantages of the proposed device include lower system cost, smaller device size and lower power consumption. This device can be implanted by minimally invasive surgery and is suitable for the localized diagnosis/therapy of cancers, or the immediate treatment of unpredictable heart attacks by releasing drugs such as nonapeptide leuprolide acetate or nitroglycerin. Physicians can also make non-invasive therapy modification by using the wireless capability.