The Investigator Site File (ISF) is the collection of essential documents maintained at a clinical trial site that demonstrates compliant study conduct.
It typically includes IRB approvals, delegation logs, training records, safety communications, protocol correspondence, and investigational product documentation. The ISF provides evidence that the investigator and site are following the approved protocol and applicable regulations. Monitors review the ISF during site visits to confirm documentation completeness and correct filing. Regulators may inspect the ISF to verify participant protections, oversight, and data integrity at the site level.