This study examined the effect of peer assessment on prospective teachers' performances in complex problem solving. This study also investigated how feedback functions, agreement with peer feedback, and feedback direction affected the use of feedback. The participants included 68 prospective teachers enrolled in the Teaching Methods-2 course during 2012-2013 spring semester and 14 prospective teachers pursuing MA studies on Computer Education and Instructional Technology. The data included prospective teachers' case solutions and MA students' feedback reports. The results indicated that groups in both feedback and non-feedback conditions improved on developing solutions for the problems. Additionally, the results showed that while feedback function and feedback direction predicted the use of feedback, prospective teachers' agreement with feedback was not related to the feedback use. Suggestions were made for further research in line with the findings. (C) 2014 Elsevier Ltd. All rights reserved.