OBJECTIVE: The 20-item Toronto Alexithymia Scale (TAS-20) measures three intercorrelated dimensions of alexithymia: (1) difficulties identifying feelings (DIF), (2) difficulties describing feelings (DDF), and (3) externally oriented thinking (EOT). The aim of the study was to test the three-factor model of the TAS-20 using confirmatory factorial analyses (CFA). METHOD: 769 healthy subjects and 659 patients meeting the DSM-IV criteria for substance use disorders or eating disorders completed the TAS-20. The correlation matrices for each of the samples were analyzed with LISREL 7.16. RESULTS: In each sample, the three-factor model was found to be replicable. CONCLUSION: The three TAS-20 subcales can be used to explore the distinct facets of the alexithymia construct.