Natural organic matter (NOM) can act as a carrier for contaminants. Therefore it is of great importance to understand its adsorption/desorption and transport behavior. NOM is a mixture of molecules varying from simple small molecules like citric acid to complicated large molecules like humic acid. To simulate sorption and transport of NOM in aquifer material, we used a previously developed model (NOMADS) describing the dynamic competitive sorption of NOM fractions. We calibrated NOMADS using independent batch adsorption data and incorporated it in a transport code. Sorption and transport of NOM in laboratory column experiments and a field experiment were well simulated using the calibrated model, indicating that the process descriptions used are valid over a wide range of temporal and spatial scales and mass-to-volume ratios. Simulation results provided insights into the influence of pore water velocity and NOM concentration history on the shape of breakthrough curves of NOM fractions. The heterogeneity of NOM appears to be essential to understanding its adsorption and transport behavior.