Friction stir processing (FSP) has been shown to produce a complex microstructure, with a fine-grained structure in the central region known as the nugget zone (NZ).  Since the material produced by FSP is being considered for superplastic applications, it is therefore necessary to find methods for stabilizing the microstructure developed by FSP. Here, we employ a second pass as a means of stabilizing the microstructure.  Two samples of aluminum alloy AA 5052 were friction stir processed at 500 rpm and 2 ipm: one with a single pass and the other with a second pass directly over the first pass. A bird’s eye-view of the entire microstructure of both samples was obtained using polarized light microscopy. Using Orientation Imaging Microscopy (OIM) in conjunction with a novel automated 3D microstructure reconstruction technique it was possible to provide a detailed study the effect of a second pass on the NZ region. The grains in the NZ of both samples are equiaxed and increase in size from the advancing side (AS) to the retreating side (RS). Furthermore, the grain size ranges from ~ 2.10 to 3.14 microns and ~1.79 to 3.23 microns in the one-pass and two-pass samples, respectively. This indicates that the application of the second pass produced little or no additional grain refinement in the NZ. The texture in the NZ was complex and ranges from weak shear to random texture, depending on the location in relation to the center on the NZ. This paper discusses the effect of two-pass FSP on the stabilization of microstructure and texture, through the analysis of 3D OIM microstructure.