Though controversy continues as to whether error feedback helps L2 student writers to improve the accuracy and overall quality of their writing (Ferris, 1999a; Truscott, 1996, 1999), most studies on error correction in L2 writing classes have provided evidence that students who receive error feedback from teachers improve in accuracy over time. One issue which has not been adequately examined is how explicit error feedback should be in order to help students to self-edit their texts. In this experimental classroom study, we investigated 72 university ESL students' differing abilities to self-edit their texts across three feedback conditions: (1) errors marked with codes from five different error categories; (2) errors in the same five categories underlined but not otherwise marked or labeled; (3) no feedback at all. We found that both groups who received feedback significantly outperformed the no-feedback group on the self-editing task but that there were no significant differences between the “codes” and “no-codes” groups. We conclude that less explicit feedback seemed to help these students to self-edit just as well as corrections coded by error type.