Over the last decade, factor analysis has been used increasingly to describe patterns of simultaneous occurrence of the central components of the insulin resistance syndrome. In this paper, the authors describe factor analysis, review studies that have used factor analysis to examine the insulin resistance syndrome, and explore how factor analysis might be used to increase our understanding of this syndrome. Most studies that they reviewed gave vague reasons for using factor analysis and did not demonstrate an understanding of the use and limitations of this statistical method. Confirmatory factor analysis based on sound theoretical concepts and a clear understanding of the statistical methods may provide some insights into the pathophysiology of the syndrome. However, to date none of the studies has adopted this approach, and other statistical approaches and study designs are likely to provide greater understanding of the syndrome.