A model is developed that predicts the growth and motion of oxide inclusions during pouring, as well as their final locations on the surface of steel sand castings. Inclusions originate on the melt free surface, and their subsequent growth is controlled by oxygen transfer from the atmosphere. Inclusion motion is modelled in a Lagrangian sense, taking into account drag and buoyancy forces. The inclusion model is implemented in a general-purpose casting simulation code. The model is validated by comparing the simulation results to measurements made on production steel sand castings. Good overall agreement is obtained. In addition, parametric studies are performed to investigate the sensitivity of the predictions to various model parameters.