Twenty-three paired skin samples from 19 autopsies without putrefaction were taken from areas of livor mortis that (1) did not blanch with finger pressure and (2) blanched with strong pressure by tweezers. Three-dimensional microscopic viewing of 100-&mgr;m benzidine-stained skin sections demonstrated small blood vessels filled with red blood cells. The diameters of the clumps of red blood cells were greater in the sections from non-blanched areas than in the blanched areas, suggesting that fixation of hypostasis soon after death depends on sedimentation of intravascular red blood cells and passive dilatation of small vessels rather than on postmortem hemolysis.