This paper examines the use of address forms in interpreter-mediated question and answer (Q&A) sessions in international conferences. The address forms analyzed include both the names and the pronouns the questioners used to address the presenters. The data were collected from two conferences held in Taiwan during which Chinese/English simultaneous interpretation were provided. The Q&A pairs were divided into three categories: (1) bilingual/multilingual communication between questioners and presenters who spoke different languages; (2) monolingual communication between questioners and presenters who spoke the same language, (3) English-as-lingua-franca communication between questioners and presenters who spoke different language but chose to use English as a common language. The results show that (1) shifts in address forms occurred most frequently in interpreter-mediated bilingual/multilingual communication, (2) simultaneous interpreters tended to conform to target-culture conventions in their renditions of address forms, even though their decisions were still influenced by the cognitive constraints ubiquitous in the process of simultaneous interpreting.