Understanding pore fluid distribution in porous media is an essential task in exploring plant growth under microgravity. This paper presented experimental and modeling investigations on pore fluid distribution at residual saturation in porous media in microgravity. First, experiments were conducted aboard NASA's KC-135 flights, which provided gravity conditions of 1g, 2g, and 0.01 g. Glass beads were used as porous media. Hexadecane, a petroleum compound immiscible with and lighter than water, was used as wetting fluid at residual saturation. Nitrogen freezer was used to solidify the discontinuous Hexadecane ganglia in glass beads to preserve the pore fluid changes during different gravity conditions. Particle separation and increased bulk volume of samples under microgravity were observed. In the modeling phase, a 3D pore network model was developed to investigate the spatial distribution of pore fluid. Cubic packing (the loosest packing) of Ottawa sand was used to represent the particle separation under 0g. The modeling results revealed non-uniform spatial distribution of pore fluid under 0g. Copyright ASCE 2006.