This paper opens by placing our current understanding of human error within a model of accident causation. The philosophical problems of bias and hindsight in accident investigation are discussed and a classification of human error types is presented. Two recent surveys of accident data and three case studies are used to highlight the main concerns in the sources of failure. These concerns are onboard violations, lack of onboard situational awareness, and failures in management practice. The paper provides an overview of how these issues have led to developments in maritime training and research. The first development has been the design of more effective training courses through a better understanding of the nature of the skill requirements of situational awareness. The current training is outlined and other areas of research, which are now being undertaken, are described. The paper concludes with a summary of further research and development needs.