The Wallops Island Instrument Intercomparison Workshop represented the first comprehensive intercomparison of techniques to measure ambient, free-tropospheric levels of carbon monoxide, nitric oxide, and hydroxyl. The workshop was conducted as part of the National Aeronautics and Space Administration's Global Tropospheric Experiment. A summary of workshop operations and the results from the ''exchange of standards'' portion of the workshop are presented. The intercomparison results from the ambient measurement portions of the workshop are discussed in other papers in this issue of the journal.