The English teachers' ability to communicate does not only mean to transmit information in a one-way manner but also to be able to negotiate meaning in order to avoid possible misunderstandings that may cause a communication breakdown. Other-initiated repair (OIR) strategies are the strategies that can be deployed to solve understanding problems that deal not only to linguistics aspect but also hearing problems, poor speech delivery, or overall misunderstanding of intended meaning by the speakers in interaction. This paper aimed at outlining the way the pre-service EFL teachers' ability in using the OIR Strategies is assessed by using task-based assessment. Theoretical and empirical arguments were provided to support the development of communicative tasks assessment consisting of the assessment instruments, procedures, validation, blue-print, and validation. The developed assessment was implemented to a group of EFL pre-service teachers in a teacher college of Widya Mandira Catholic University in Indonesia. The result showed that the students were able to employ a set of OIR strategies to address the understanding problem in the interaction with their peers. It is concluded that the communicative task assessment is an effective way to elicit the students' ability in using OIR Strategies in the interaction so it should be incorporated in the speaking instruction to enhance the students communicative competence.