Magneto‐optical media using ultrathin Co/Pt and Co/Pd films were prepared on 2P (photopolymer) glass substrates with a double‐layer disk structure. Thermomagnetic writing was successfully made in the magneto‐optical disks by the relatively low laser power above 3 mW. The values of the C/N ratio were 50 dB for the Co/Pt disk and 45 dB for the Co/Pd disk at a bit length of 5 &mgr;m. Clear and regular bit domains were observed even in the shorter recorded bit length.