The objective of this article was to evaluate the Gabrieli Medical Nomenclature (GMN) as a coding system for primary care, using a system of five criteria. These were: the infrastructure supporting the coding system; the code structure; ease of use of the codes; the reproducibility of coding; the usefulness of the codes to Australian GPs. The performance of the GMN was evaluated as being at, or below the level of other coding systems in each of the assessment areas. It was found that the GMN has no advantages over other, existing coding systems. Evaluation of coding systems should include an assessment of the reproducibility of coding and its usefulness to Australian general practice.