Institutional integrated TeleTanDem (iiTTD) is a model of telecollaboration characterised as a series of tasks that are integrated into the syllabus of a foreign language course. This paper aims at presenting and discussing the assessment practice of a Brazilian teacher who integrated teletandem into her regular English as a Foreign Language (EFL) lessons within a teacher education programme. Among the different tasks that learners carry out within iiTTD, this study focusses on what is assessed by the teacher when offering formative feedback on learning diaries written by Brazilian participants. The study, of a qualitative interpretative nature, uses data collected by means of the tasks that 13 Brazilian learners carried out within iiTTD in 2017. Results show that the teacher was able to assess (1) students' self-assessment skills, (2) language accuracy (when diaries are written in English), (3) the learning of content presented in class, and (4) intercultural issues that may emerge during teletandem oral sessions. [For the complete volume, "Telecollaboration and Virtual Exchange across Disciplines: In Service of Social Inclusion and Global Citizenship," see ED596376.]