Basement permeabilities were found to be high during both open-hole flow and packer experiments, roughly consistent with modeling results, but significant differences in apparent permeabilities suggest that there may be a scale dependence of these properties (Fisher et al., 1997; Davis and Becker, 1999; Davis et al., 1999; Davis et al., in press; Becker and Fisher, 2000). In addition, when Leg 168 packer data from the uppermost basement were combined with measurements from elsewhere around the world, a consistent permeability-age trend was identified (Becker and Fisher, 2000). Differences in basement permeability inferred using different methods and assumptions may indicate that a large fraction of the fluid flux through oceanic basement is concentrated within a small volume of rock (Fisher and Becker, 2000), an interpretation consistent with the heterogeneous nature of basement alteration (Marescotti et al., Chap. 10, this volume; Hunter et al., 1999).