In an effort to improve patient safety, researchers at the Johns Hopkins University designed and implemented a comprehensive Web-based Intensive Care Unit Safety Reporting System (ICUSRS). The ICUSRS collects data about adverse events and near misses from all staff in the ICU. This report reflects data on 854 reports from 18 diverse ICUs across the United States. Reporting is voluntary, and data collected is confidential, with patient, provider, and reporter information deidentified. Preliminary data include system factors reported, degree of patient harm, reporting times, and evaluations of the system. Qualitative and quantitative data are reported back to the ICU site study teams and frontline staff through monthly reports, case discussions, and a quarterly newsletter.