The recognition of flow regimes is very important in the application of spouted beds. In this paper, two-dimensional computer simulations of a slot-rectangular spouted bed using FLUENT commercial software were utilised to construct flow regime maps. Two-phase gas–solid flows in the bed were simulated with computational fluid dynamics (CFD) using the two-phase Eulerian–Eulerian granular model. The numerical simulations were applied to predict different flow regimes. The constructed flow regime map for a bed containing solid particles with a diameter of 1.44 mm was in good agreement with the experimental map previously reported elsewhere. With this successful numerical mapping, a flow regime map for particles with a diameter of 3.77 mm was constructed for various superficial gas velocities and static bed heights. The map was composed of six distinct flow patterns, that is fixed bed, internal jet, jet-in-fluidised-bed, spouting, incoherent spouting and slugging. The slugging flow regime occurred at large values for the static bed height and air inlet velocity, while the spouting regime arose by increasing the air inlet velocity at low values of static bed height. Unlike the spouting regime, large pressure drop fluctuations were observed in the incoherent spouting regime.