The lowest level ESL students in a college or university writing program usually represent a small, seldom-studied population. However, administrators and instructors concerned with retention and counseling need data on this group of high-risk students to improve their chances of succeeding academically. A significant percentage experience academic difficulty in English composition and other classes. A study of entrance exam essays and test scores of 70 low-level ESL university students was done to determine if students’ later success or failure in ESL and mainstream composition courses could be predicted. Twelve of 20 variables analyzed proved statistically significant in predicting success or failure. Language factors, sentence clarity, and identifiability of errors were significant. Factors related to essay organization and development and scores from campusdeveloped reading, grammar, and cloze tests also proved significant. The information from this study gives instructors and program administrators concrete, measurable warning signals for identifying potentially high-risk ESL writers.