Background: Obesity presents major challenges to public health in the United States. Trials of web-based interventions for weight control suggest that the Internet is a promising option for program delivery. Purpose: This study sought consensus among experts regarding critical components of successful weight control and to systematically examine popular websites for evidence of this best practice. Methods: A panel of 11 weight loss intervention researchers and program administrators rated, from an extensive list gleaned from the literature, the most important attributes necessary for successful weight loss programs. The researchers assessed the 20 highest ranking weight control websites, identified through organic search, for the presence of the attributes recommended by the panel. Results: Most of the top 20 websites provided limited information for the majority of the recommended attributes. Two websites were more popular than the remaining 18. Translation to Health Education Practice: Health education specialists must recognize the great numbers of adults and youth who regularly search the Internet for information and programs related to weight loss. Health education should collaborate with other disciplines to develop online programs based on behavior change theory and successful weight loss techniques and assure that these websites can be found through organic search engines.