The purpose of this chapter is to present the assessment practice carried out by means of learning diaries within institutionally integrated teletandem, a bilingual model of Virtual Exchange (VE) embedded into foreign language courses at São Paulo State University (UNESP), in Brazil. Teachers read learners' diaries on a weekly basis and provide one-to-one feedback related to (1) telecollaborative learning processes, (2) difficulties and affective factors, and (3) linguistic aspects. This asynchronous form of assessment in the form of teachers' feedback on learners' diaries not only guides each individual learner's autonomous learning, but also allows teachers to select relevant information to be used in synchronous group discussions and teaching in face-to-face lessons.