Specimens containing surface cracks were tested in either tension or bending to compare the stress intensity factor at failure with plane strain fracture toughness (K_Ic) in an International Cooperative Test Program. The material was heat treated to σ_ys = 1 587 MPa and K_Ic = 54 MPan^1/2. Because substantial stable crack growth occurred for some specimens, the test plan was modified to include detecting the onset of crack growth. It is shown that P_max and the original fatigue precrack size cannot be employed to calculate K_max for comparison with K_Ic when significant stable crack growth occurs. However, using P_init (load at which stable crack growth is initiated) and the original fatigue precrack size to calculate K_max or K_ϕ=30° provides a very useful comparison with K_Ic. The influence of variations in fatigue precrack configuration on test results are also discussed.