Superelastic Nitinol wires (A_f = 5^oC, 0.8mm diameter) were tested under rotary-bend fatigue conditions from 0.5% to 4.5% strain at 20^oC up to 10 million cycles. Samples were first electropolished to obtain a uniform smooth surface and then immersed in H3PO4 at 80^oC for various times to charge with hydrogen. Hydrogen levels of 30, 50 and 80 wppm were compared to control samples with nominal 10 wppm. These levels were chosen to address the ASTM F2063 specification of 50 wppm in wrought Nitinol alloys. In the low-cycle region (<10,000 cycles, strain >1.3%) the 50-wppm samples show a statistically significant decrease in fatigue life compared with the control samples (p<0.05). In contrast, there were no significant differences in the fatigue life with up to 80 wppm hydrogen in the high-cycle fatigue region. These results will be discussed in relation to recent structural studies of hydrogenated Nitinol.