The 68 National Cancer Institute (NCI)-designated comprehensive and cancer centers have been tasked with leading the campaign in the fight against cancer, as well as providing education and outreach to the public. Therefore, it is important for these organizations to have an effective online presence to disseminate information and engage patients. The purpose of this study was to assess both the functionality and usability of cancer centers’ websites. The 68 center web domains were evaluated using two separate but complementary approaches. First, a webcrawler was used to score each website on five dimensions: accessibility, content, marketing, technology, and usability. Rankings on each dimension and an average ranking were calculated for all 68 centers. Second, a three-reader system was used to determine a list of all functionalities present on the websites. Both webcrawler scores and functionality prevalence were compared across center type. No differences were observed in webcrawler scores between comprehensive and cancer centers. Mean scores on all dimensions ranged between 5.47 and 7.09. For the functionality assessment, 64 unique functions were determined and categorized into 12 domains, with the average center possessing less than 50 % of the functions. This census assessment of NCI centers’ websites suggests the need for improvement to capitalize on new dissemination platforms available online. Progress in development of this technology can help achieve the goals of public education and outreach to a broad audience. This paper presents performance guidelines evaluated against best-demonstrated practice to facilitate social media use improvement.