Physical appearance is very important among adolescents and young adults. Eating disorder (ED) is one of the most common fatal mental illnesses found during this development stage. Screening for unhealthy eating behaviors among this population might help to identify individuals that are at-risk for developing ED. Awareness of the prevalence and risk factors associated with this disorder will help to facilitate early diagnosis and intervention. This cross sectional study was conducted among university students aged 18-24 years using the Thai version of the Eating Attitudes Test (EAT-26) as a self-administered questionnaire. Of the 385 students selected by random sampling and proportion allocation were recruited in this study, 326 (84.7%) completed the EAT-26. Of these, 56% were female, 3.7% were obese, 9.9% were overweight, and 16.7% were underweight. One hundred forty (43.5%) participants felt they were too fat and tried to lose weight, while 3.4% were always preoccupied with a desire to be thinner. Females expressed a desire to be thinner (61.9% vs 38.1%; p=0.003) and had a history of being on a diet (63.8 % vs 36.7%; p=0.022) more than male respondents. Prevalence of students at-risk for ED, defined as EAT-score >= 20, was 4.3%. From univariate analysis, the risk factors associated with an EAT-26 score of >= 20 included: history of practicing food restriction ([odds ratio (OR) =19.231]); self-perception of being too fat (OR=8.4); a desire to be thinner (OR=1.069); and, history of father practicing food restriction (OR=5.025). On multivariate analysis, history of practicing food restriction (OR=19.231) and self-perception of being too fat (OR=8.4) were identified as significant independent risk factors for ED. The number of adolescents at-risk for developing an ED was high in this study, but comparable with the results of other Asian studies. Consistent with these findings, periodic screening and the development of an early prevention program is recommended.