AbstractMagnetic circular dichroism (MCD) measurements are carried out on Si monocrystals in longitudinal magnetic fields up to 5.3 T. Near the indirect excitonic absorption many oscillations occur in the MCD spectra. In comparison with wavelength‐modulated absorption measurements it is shown that the MCD oscillations are due to strongly broadened steps in the absorption edge. The characteristic energies of the absorption steps behave like that of Landau levels with a phenomenological effective mass ofm* = 0.38 ± 0.04 forB| [001], obtained also by cyclotron resonance experiments. The energies of the Landau‐like steps converge withB→ 0 to energies near the series limit of the exciton. It seems to be the first time that Landau levels in the magnetoabsorption in Si are me