The effect of stress state on threshold stress intensity and crack growth rates was studied in Ti-6A1-6V-2Sn containing 38 ppm hydrogen. Threshold stress intensities approached a lower limiting value near 32 MPa-m1/2 as total plane strain conditions were approached. Under increasing plane stress conditions, thresholds increased significantly toward a value indicating immunity from hydrogen effects. Crack growth rates depended on both stress intensity and stress state. The thinner samples required much greater stress intensities to achieve crack growth rates comparable to the thick samples. This was due to plane stress plastic zones at the sample surfaces acting as a constraint on crack opening. Under plane strain conditions, fracture was characterized by extensive cleavage of the a grains. Fracture occurred by a ductile mode in the plane stress regions. A threshold model based on hydride formation and fracture was modified to account for stress state effects. The predicted stress intensities were in good agreement with the observed values.