N-Isopropylacrylamide (NIPA) hydrogel was successfully incorporated with tributyl phosphate (TBP) which works as an extractant species of phenols. NIPA hydrogel was found to be favorable to prepare a monolithic hydrogel in the coexistence of TBP which requires using methanol as the polymerization medium. The hydrogel was found to be stably obtained at 333 K in methanol and the concentration of crosslinker (N,N'-methylenebisacrylamide) of 86 mM. The TBP-incorporated NIPA hydrogel was used for experiments for removal of phenol from aqueous solution. The removed amount of phenol using the NIPA hydrogel was markedly enhanced in proportion to the amount of incorporated TBP. Liquid-liquid solvent extraction of phenol using TBP dissolved in n-octane was examined for comparison of the distribution ratio D. From the proportional dependence of the distribution ratio on the amount of the incorporated TBP, phenol was found to form a 1:1 complex with TBP both in the cases of NIPA gel and liquid-liquid solvent extraction. At the corresponding concentration of phosphate moiety, the phenol removal performance by the TBP-incorporated NIPA hydrogel was found to be comparable to that by conventional liquid-liquid extraction.