Widespread production and application of manufactured nanomaterials will inevitably lead to the release of nanoparticles into the environment. The current understanding of nanoparticle fate and transport in subsurface environments, however, is quite limited. In this work, we seek to advance our understanding of the transport and retention of C-60 fullerene (95 nm dia.) in water-saturated soils through a combination of experimental and mathematical modeling studies. A series of transport experiments was conducted at several pore-water velocities in glass columns packed with various size fractions of Ottawa sand. Effluent concentration and particle retention data were simulated using a mathematical model that incorporated traditional filtration theory with rate-limited, nonlinear surface blocking behavior. The numerical model successfully captured the characteristics of both the effluent concentration and particle retention profiles. The experimental and simulation results suggest that C-60 fullerene particle attachment is strongly dependent on porous media surface area and flow rate. Simulated attachment capacity increased with increasing specific surface area, and for a given sand size fraction, simulated n-C60 attachment rates were greater at higher flow rates. Extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, incorporating van der Waals, electro-static repulsion, and hydrophobic interaction forces, was used to evaluate potential mechanisms governing C-60 attachment. This analysis suggests that a sizable energy barrier of about 22 kT exists between C-60 fullerene particles and Ottawa sand surfaces and that there is a very small secondary minimum attraction region with depth of 0.12 kT. Additional studies are being conducted to further elucidate the forces responsible for n-C60 particle retention.