Due to its complexity intensive care is vulnerable to errors. On the ICU Adults of the AMC (Amsterdam, the Netherlands) the available registries used for error reporting did not give insight in the occurrence of unwanted events, and did not lead to preventive measures. Therefore, a new registry has been developed on the basis of a literature study on the various terms and definitions that refer to unintended events, and on the methods to register and monitor them. As this registry intends to provide an overall insight into errors, a neutral term ('incident') –which does not imply guilt or blame- has been sought together with a broad definition. The attributes of an incident further describe the unwanted event, but they should not form an impediment for the ICU nurses and physicians to report. The properties of a registry that contribute to making it accessible and user friendly have been determined. This has resulted in an electronic registry where incidents can be reported rapidly, voluntarily, anonymously and free of legal consequences. Evaluation is required to see if the new registry indeed provides the ICU management with the intended information on the current situation on incidents. For further refinement of the design, additional development and adjustments are required. However, we expect that the awareness of errors of the ICU personnel has already improved, forming the first step to increased patient safety.