Effective information mining for legal terminological research in translation is largely determined by the ability to contextualize concepts in their legal framework and to resort to relevant legal sources. Specialized knowledge of these sources thus emerges as a competence marker that is expected to converge with that of comparative law practitioners. Against this background, a survey was conducted in order to examine institutional translators' use of resources for translation in general and their perceptions of sources for legal translation in particular. The data provided by 234 respondents from 12 international organizations offer a comprehensive portrait of translation professionals and information-mining practices in these settings. Profile features in terms of legal translation frequency, main translation specializations and academic backgrounds were correlated to relevance and reliability scores assigned to the sources used for legal terminological research. The results confirm several hypotheses based on generally accepted indicators of specialization in this field, including the prioritization of monolingual lexicographical resources over bilingual ones and the higher reliability of primary legal sources over institutional terminological databases and previous translations. Common patterns and variations between institutions and profiles, as well as their implications for institutional terminology management and translation quality, are briefly discussed.