Good evaluation practice guidelines have been developed through a consensus making process by a core team and the health informatics community. A set of 60 issues has been identified that is relevant for planning, implementation and execution of an evaluation study in the health informatics domain. These issues cover all phases of an evaluation study: Study exploration, first study design, operationalization of methods, detailed study design, execution and finalization of an evaluation study. Issues of risk management and project control are also addressed in the guidelines. Through application of these guidelines the general validity and generalization of evaluation studies are likely to be increased, since these guidelines aim at avoiding a number of omissions, pitfalls and risks.