So far, design and deployment of microelectronic, implantable devices has largely had a strongly "ad-hoc" character. The majority of existing devices has been custom-tailored to the specific application in mind, in an effort to abide by strict design constraints on safety as well as power and size. However, an enabling technology and the fact that implants are gradually becoming mainstream market products calls for a more structured design approach. Towards that end, in this paper we present ImpBench, a novel benchmark suite meant for designing and evaluating new digital processors for microelectronic implants. In an application field as wide as the various pathoses of the human body, we have conceptualized this suite based on common-sense and market-driven indicators, and we have established its usefulness and uniqueness based on extensive experimental measurement. The suite consists of eight carefully selected programs, chosen on the basis of popularity among contemporary and emerging implant applications. MiBench being the closest to our application field, that is embedded systems, has been used for a detailed comparative study. Since implants are required to perform control-, processing- or I/O-intensive tasks, various benchmark characteristics have been studied, namely: performance (IPC), cache and branch-prediction behavior, instruction distribution and power consumption. Results display significant variation from existing benchmarks to justify the need for and usefulness of ImpBench.