AIMS: Danish women aged 16-29 from two nationwide, representative, cross-sectional interview/questionnaire surveys from 2000 and 2005 are analyzed for trends in prevalence of risk behaviour for developing eating disorders and associations to BMI and age. METHODS: Participants completed the Danish Health Interview Survey and an 8-item screen, RiBED-8, for risk behaviour for eating disorders. To analyze how the prevalence of risk behaviour depends on age, BMI, and year of survey, logistic regression analyses were applied. On acceptance of no interaction, the effect of each variable was tested and described using odds ratios with 95% confidence intervals. RESULTS: Women aged 16-19 or with a BMI of>25 had the greatest chance of reporting risk behaviour for eating disorders. However, many women in their 20s also had risk behaviour. Prevalence of risk behaviour for eating disorders did not change from 2000 to 2005. CONCLUSIONS: The shared risk factors for obesity and eating disorders require further investigation for development of collaborative prevention and treatment strategies that should also be directed towards young women in their 20s as well as young teenagers.