The National Toxicology Program (NTP) performs comprehensive testing on test articles including toxicology/carcinogenicity assessments, immunology and reproductive assays, high throughput screening assays, and genetic toxicology testing. Over the past ten years NTP data for over 11,000 test articles have been deposited into the Chemical Effects in Biological Systems database (CEBS: http://cebs.niehs.nih.gov). Previously, NTP conclusions and calculated statistical summary data for a selected test article could only be reviewed in individual study views by study type making it difficult to review data across study types for a CAS number. The new NTP Treatment-Related Findings guided search tool integrates NTP data in CEBS allowing users to retrieve and compare NTP summaries and conclusions across one or more study types. Users can input a single CAS number or list of CAS numbers to view a single data table containing user specified endpoints such as NTP levels of evidence of carcinogenicity activity and summaries such as statistically significant neoplastic and non-neoplastic lesion incidence calculated from NTP data. Statistically significant lesion incidence can be filtered by lesion type, organ site, and animal strain. Presented in this way users can review all selected conclusions and summaries for a given chemical and compare multiple chemicals across rows. Supporting data is made avail-able by selecting an expanded view to display treatment related group summaries for lesion incidence. Genetic toxicology data are accessible using the same search criteria with NTP conclusions at the study and trial level available for all NTP assay types. Published NTP technical reports are linked for each chemical so the full NTP presentation of results is quickly accessible for further evaluation. All data returned by the Treatment-Related Findings guided search can be downloaded in Excel worksheets. The Treatment-Related Findings guided search tool can be accessed at: http://tools.niehs.nih.gov/cebs3/ncsw/.