An instrumented creep testing capability is being developed for specimens irradiated in pressurized water reactor coolant conditions at the Advanced Test Reactor (ATR). A test rig has been developed such that samples will be subjected to stresses up to 350 MPa at temperatures up to 370°C in pile. Initial Idaho National Laboratory (INL) efforts to develop this creep testing capability for the ATR are summarized. In addition to providing an overview of in-pile creep test capabilities available at other test reactors, this paper reports efforts by the INL to evaluate a prototype test rig in an autoclave at INL's High Temperature Test Laboratory. Data from autoclave tests with Type 304 stainless steel and copper specimens are reported.