Purpose: The purpose of this report was to investigate the relation between dry eye diagnostic tests. Methods: Dry eye patients were enrolled to complete a clinical examination, including the following dry eye tests: a meibomian gland evaluation, tear meniscus height, fluorescein tear breakup time, fluorescein staining of the cornea, the Schirmer 1 test, the phenol red thread test, and rose bengal staining of the conjunctiva. Statistical analyses, including correlation coefficients, the Wilcoxon sign rank test, chi-square test, and logistic regression were used to address the relation between these clinical tests of dry eye. Results: There was a strong relation between the Schirmer test and fluorescein staining in all four statistical analyses. Similarly, there was also a strong relation between the phenol red thread test and both fluorescein and rose bengal staining. Finally, the results of the Schirmer test were associated with the tear breakup time test in three of four analyses. Conclusions: The results indicate that tests of aqueous deficiency (volume or production) are associated with ocular surface desiccation. This important relation should be recognized when choosing dry eye tests as outcomes in clinical trials and epidemiological studies. © 2003 The College of Optometrists.