This chapter describes the methodological framework related to the use of verbal reports to elicit data on mental processing as outlined by Ericsson and Simon, discusses relevant research evidence in translation process research (TPR), and highlights the need for systematic methodological research on verbal reports in translation studies. It introduces the basic assumptions of Ericsson and Simon's “theory of verbalization” to discuss its application and potential problems in relation to investigating translation processes. Then, an overview of the existing methodological studies in TPR, focusing on concurrent verbal reports (think-aloud) and retrospection is presented. The chapter also provides an overview and describes the state of the art of using verbal reports in TPR and identifies potential areas for further research and theoretical exploration. It focuses on written translation, although verbal reports are used in interpreting research as well; and orally produced verbal reports, although written retrospective reports could also be regarded as verbal reports.