Hole 504B, about 200 km south of the Costa Rica Rift in the eastern equatorial Pacific, has been drilled over a succession of Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) legs to a total depth of 2000.4 meters below seafloor (mbsf). Borehole televiewer (BHTV) measurements were recorded over the intervals 275-497 mbsf on Leg 137, and 1497-1715 mbsf and 1868-1990 mbsf on Leg 140. Detailed investigation of the BHTV data revealed stress-induced wellbore breakouts in all depth intervals with variable occurrence. The statistical analysis of the wellbore breakouts shows that the orientation of the maximum horizontal stress (S Hmax ) varies from N53°E ± 28° in the interval 410-490 mbsf, to N21 °E ± 35° in the interval 1497-1715 mbsf, and N82°E ± 38 in the interval 1868-1990 mbsf. Whereas the intermediate depth interval shows a mean azimuth that is consistent with previous observations from borehole breakout analysis between 700 and 1500 mbsf, the upperand lowermost breakout intervals are rotated clockwise by 22° and 61°, respectively. As none of the observed intersecting structures correlates with the observed rotation ofS Hmwc , it is assumed that the rotation is affected by non-intersecting structures or structures beyond the wellbore head. The onset of the breakout interval from 410 to 490 mbsf correlates well with the Layer 2A/2B boundary and corresponds to a seismic anisotropy observed in the upper 500 m of the crust. For breakouts to occur in shallow depths, high S Hma jS hmin ratios are required or rock strengths must locally vary (to values