Acoustic surface wave attenuation in LiNbO3caused by ion implantation was studied as a function of fluence and surface wave frequency. 80‐keV Ne+ions were implanted at five fluences covering the range 1014–1016ions/cm2. TheyzRayleigh surface waves were generated spanning the interval 100–1000 MHz by interdigital transducers operating at odd harmonics. Attenuation was measured directly by a standard laser probe using reflected light. At low acoustic power densities, the data can be fit byP(z)/P0=10−Af2z, wherePis acoustic power,fis the surface wave frequency, andAis a constant for each fluence used. The values ofAshow a definite peak with fluence at around 1015ions/cm2, whereA=9 × 10−5dB cm−1MHz−2±10%. This is about twenty times the value ofAfor an unimplanted surface.