The dual-frequency Airborne Precipitation Radar-2 (APR-2) was deployed during the Wakasa Bay Experiment in 2003, for validation of the Advanced Microwave Scanning Radiometer–EOS. Besides providing extensive observations of diverse precipitating systems, this Ku-(13.4 GHz) and Ka-band (35.6 GHz) cross-track scanning radar measured sea surface backscatter simultaneously. While the characteristics of the normalized sea surface cross section 0 at Ku-band are well understood and widely published, the existing experimental data concerning 0 at Ka-band are scarce and results are inconsistent. In this letter, the Ku/Ka-band 0 measurements collected by APR-2, together with the estimated uncertainties, are discussed. In general, the measured 0 at Ka-band at around 10 incidence angle appears to be close to that at Ku-band 0 , and Ka-band exhibits a nonnegligible difference in wind dependence with respect to Ku-band for moderate to high winds.