Increases in immigration have led to an enormous growth in the number of cross-linguistic medical encounters taking place throughout the United States. In this article the role of hospital-based interpreters in cross-linguistic, internal medicine ‘medical interviews’ is examined. The interpreter's actions are analyzed against the historical and institutional context within which she is working, and also with an eye to the institutional goals that frame the patient-physician discourse. Interpreters are found not to be acting as ‘neutral’ machines of semantic conversion, but are rather shown to be active participants in the process of diagnosis. Since this process hinges on the evaluation of social and medical relevance of patient contributions to the discourse, the interpreter can be seen as an additional institutional gatekeeper for the recent immigrants for whom she is interpreting. Cross-linguistic medical interviews may also be viewed as a form of cross-cultural interaction; in this light, the larger political ramifications of the interpreters' actions are explored.