This proposal describes the US arm of a multinational study of medical errors in family practice. Using a web-enabled survey instrument that collects both quantitative and qualitative data, the study seeks to: (1) define the types of medical errors that are recognized and reported in family/general practice in the United States, and (2) compare them to those recognized and reported in Australia, Canada, Great Britain, the Netherlands, and New Zealand. Specifically: What are they? Where do they happen? When do they i happen? Who do they happen to? The US arm of the study alone will comprise free text reports of between 300 to 600 errors, and the entire study will include between 2,000 and 3,000 reports. The study's hypotheses are that: (1) Family doctors in these countries will report errors and strategies for avoiding further errors. (2) There are important lessons to be learned from the similarities and differences in the errors and prevention strategies from the six participating countries.