A systematic investigation was undertaken to examine the influence of experimental variables on the measurement of stress corrosion cracking (SCC) properties of two high-strength steels using fracture mechanics test procedures. The properties of interest were the SCC threshold stress-intensity (KISCC) and time-based crack growth rate (da/dt). Two quench-and-tempered alloy steels in the form of rolled plate material were tested. The steel had yield strengths of 965 MPa (140 ksi) and 1207 MPa (175 ksi). The primary experimental variables investigated included: (1) specimen type (bolt-loaded wedge-opening loaded (WOL) and cantilever beam); (2) bulk solution chemistry (3.5% NaCl in distilled water and natural seawater); (3) dissolved oxygen content of the bulk solution; (4) electrode potential (open circuit and -1.0 V versus Ag/AgCl); (5) method of applying cathodic protection (potentiostat and zinc couple; (6) precracking stress-intensity level; (7) initial applied stress-intensity level; and (8) test duration. The effects of these experimental variables on KISCC and da/dt measurement are reported and the implications of these findings on test method development are discussed.