The actual classroom implementation and the possible final outcomes of the genre based approach to writing assessment and portfolio assessment have not been fully explored yet. The present quasi-experimental study investigated the effects of genre-based assessment and portfolio assessment on EFL learners' writing performance on letter-writing task. The experiment involved 45 Iranian intermediate students that were randomly assigned to two experimental groups and one control group. The participants of the first experimental group were asked to write a letter of application through a genre-based technique. The participants in portfolio group were asked to write application letters through portfolio approach. The Control group based on the traditional approach just received their scoured writings without any oral and written feedback by the teacher. The result of the study showed that there was significant difference, between performances of the two experimental groups and that of the control group on the post test. No significant difference was found between the performance of the two experimental groups after implementing portfolios and genre assessment.
