This paper describes how to evaluate an automated ECG analyzer using available annotated ECG databases and software, in compliance with standard evaluation protocols. These protocols have been adopted as parts of the American National Standard for Ambulatory Electrocardiographs (ANSI/AAMI EC-38, 1994); they include earlier evaluation protocols developed for an AAMI Recommended Practice, Testing and Reporting Performance Results of Ventricular Arrhythmia Detection Algorithms (AAMI ECAR, 1987). It will be most useful to readers who plan to use the suite of evaluation software included in the DB Software Package available from MIT; this suite of software includes the reference implementations of the evaluation protocols specified in EC-38.