Peer review has become commonplace in composition courses and is increasingly employed in the context of telecommunication technology. The purpose of this experiment was to compare the effects of anonymous and identifiable electronic peer (e-peer) review on college student writing performance and the extent of critical peer feedback. Participants were 92 undergraduate freshmen in four English composition classes enrolled in the fall semesters of 2003 and 2004. The same instructor taught all four classes, and in each semester, one class was assigned to the anonymous e-peer review group and the other to the identifiable e-peer review group. All other elements--course content, assignments, demands, and classroom instruction--were held constant. The results from both semesters showed that students participating in anonymous e-peer review performed better on the writing performance task and provided more critical feedback to their peers than did students participating in the identifiable e-peer review.