The purpose of the present study was to investigate the relationship between instructors' written corrective feedback and graduate students' written performance, as well as to examine the students' attitudes towards instructors' written corrective feedback. The participants of the study were graduate students, studying at the American University of Armenia, at Department of English Programs. The data for the research was gathered from the students' written assignments written throughout one term (fall, 2009). The instruments that were used for collecting data were: four Mini Projects written during the course Advanced Methodology and a questionnaire. The data collected from the Mini Projects was analyzed using the Friedman and Wilcoxon tests, in order to see the difference between the percentages of errors among the four Mini Projects. The data collected through the questionnaire was analyzed qualitatively. This study revealed that there was a significant difference among the four Mini Projects written throughout the term.