Eating disorders represent a growing national health concern and the prevalence of these disorders has been rising at an alarming rate, especially among adolescent women. While much current psychological and physiological research has focused on the development and causes of these problems, the major underlying mechanisms responsible for disordered eating patterns such as binge eating, dietary restriction, and purging episodes have yet to be discovered. The objectives of the study were to examine the heritability of certain disordered eating behaviors and attitudes and body mass index (BMI), and to investigate the effects of three previously implicated genes on eating attitudes and behaviors, DRD4, DAT1, and 5-HTTLPR. This investigation found a significant association between the short allele of 5HTTLPR and disordered eating, but failed to demonstrate an association between disordered eating patterns and DAT1 or DRD4. Analyses also indicated significant additive genetic and nonshared environmental influence on disordered eating behavior and BMI. Implications for interventions in the prevention and treatment of eating disorders are discussed.