Exciton confinement in a two-dimensional electron gas under the influence of an inhomogeneous magnetic field is studied in this work. The effective potential confines the two-dimensional electron gas to a region under the disk. Firstly the results of a detailed calculation for the eigenenergies and wave functions of the confined exciton,for four different substrates of technological interest, are obtained and discussed. The allowed transition probabilities between the energy states as a function of the strength of the magnetic field are estimated for GaAs. This antidot confinement makes the excitons very sensitive to spin orientation.The spin down state (mz = –1) increases the confinement. The exciton becomes more localized in the antidot region as the applied field increases. In contrast, the spin up state does not result in a significant localization of the exciton within the antidot region. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)