Effects of radiation damage on deuterium trapping in tungsten were investigated using SIMS/NRA and TDS techniques. Radiation damage of ∼4.8 dpa was produced by 300 and 700 keV hydrogen ions, then deuterium ions were implanted at 473 K to fluences of 0.5–8.0 × 10 24 D +/m 2. Deuterium concentration at ∼0.1 μm in depth was saturated at the lowest fluence (∼5.0 × 10 23 D +/m 2), while the D retention at ∼1.0 μm deep was not saturated at the highest fluence of ∼8.0 × 10 24 D +/m 2. On the other hand, deuterium behavior simulated by the TMAP7 code showed that the defects were filled with the implanted D from the top surface and all of the traps were filled at the fluence of ∼7.5 × 10 22 D +/m 2, which was much lower than the fluences in this experiment. TDS spectra suggested that the implanted D was trapped at the radiation-induced defects which had desorption peaks at ∼770 and ∼920 K.