Selected PFAS (per- and poly- fluoroalkyl substances) with no in vivo toxicology data are being evaluated. The primary endpoints in these studies are hepatic and renal high throughput transcriptomics, in male and female rats exposed for 5 days. Traditional toxicological endpoints (eg organ weights and clinical chemistry) have been added to the studies to provide additional contextualizaing information (i.e., phenotypic anchoring).These data will be used for determining provisional pathway-based transcriptomic BMDs for use in human health risk estimations. Key Words: benchmark dose model, high throughput transcriptomics, PFAS