During the last 20 years, safety evaluation of medical devices has evolved from screening assays to the “pharmaceutical model” of preclinical testing. Biocompatibility testing guidelines for medical devices are published in the International Organization for Standardization (ISO) document 10993–1: Biological evaluation of medical devices—Part 1: Evaluation and testing. These guidelines are recognized by most national regulatory bodies and supplement, but do not supersede, the guidelines published by the individual nations or the testing requirements for a specific medical device. The ISO 10993 series includes screening tests for nonspecific mechanisms of toxicity (cytotoxicity, acute systemic toxicity, subchronic toxicity, local toxicity, and chronic toxicity) and specific mechanisms (blood compatibility, genotoxicity, carcinogenicity, pyrogenicity, and reproductive and developmental toxicity). Other ISO 10993 standards cover chemical characterization of materials, degradation products, toxicokinetics, sample preparation, permissible limits of sterilization and process residues, and clinical studies. This review examines the scope of these standards and identifies exceptions between these guidelines and selected national and vertical standards for medical devices.