The present paper focuses on the translation process, particularly on the features of the expert translation process, viewing expertise in translation as a specific case of expertise in general. It utilises conceptual and methodological tools developed in cognitive psychology. In this paper, translation is conceptualised as problem-solving and translation tasks as ill-defined problems. We argue that professionalism does not equal expertise. Four criteria of expertise are discussed with special reference to expertise in translation. The work of experts is viewed as progressive problem-solving. Translation problems are defined as entire translation tasks, rather than single textual elements or contextual issues. Translation tasks are defined as ill-defined problems, as they are not unambiguous with only one possible solution. In addition, there is no clear solution path from the initial to the final state. Think-aloud experiments were conducted with four expert and two non-expert translators to study how different competence profiles affect the translation process and its outcome. The findings support earlier research indicating that translation does not become easier with growing experience and expertise. We suggest that a productive line of research might be investigating the constraints which direct the translation process.