We prepared lectin-imprinted hydrogel layers on surface plasmon resonance (SPR) sensor chips by atom transfer radical polymerization (ATRP). In a buffer solution with a target protein, the SPR signal and binding constant of the lectin-imprinted hydrogel layer chip were much larger than those of the nonimprinted hydrogel layer chip prepared without using a template lectin. By molecular imprinting with ATRP, recognition sites for the target lectin were formed within thin hydrogel layers on the SPR sensor chips. The lectin-imprinted hydrogel layer chips with recognition sites for target protein are candidates for highly sensitive sensor devices for an SPR sensing system.