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Ultrasonic fatigue has been employed to examine the fatigue behavior of Ti-6Al-2Sn-4Zr-6Mo in the range of 10(exp6) to 10(exp9) cycles. Fatigue tests have been conducted at stresses, sigma/sigma(gamma), ranging from 0.45-0.62 for two different heats of material. The variability in fatigue lifetimes was 2.5-3 orders of magnitude at all stress levels. Facets, which correspond in size to large primary alpha grains, were found at the sites of crack initiation. Observation of the crack initiation sites did not reveal morphological features that could be correlated with variability in lifetime. Surface and subsurface crack initiation sites were found to exhibit similar lifetimes. In general, the amount of faceted failure in the region of crack initiation was greater than that observed as the crack propagated. The topography of the fracture surface was quantified and shows that most of the facets are oriented nearly normal to the stress axis.