A search was made for absorption by O2(a1Δg) in the wavelength region 190--290 nm. Measurements were done at 10 nm intervals with a grating spectrometer having a bandwidth of 9.0 nm. No absorption above the detection limit of 0.02--0.03% absorption could be observed for O2(a1Δg) concentrations of (4--7)¿1015 cm-3. An upper limit of 8¿10-22 cm2 for the absorption cross section of O2(a1Δg) in this wavelength region was calculated.