Injectable Collagen Implan, is composed of purified bovine dermal collagen emulsified in saline and lidocaine(0.3%) base, and has been promoted for correction of soft tissue contour defects. Although collagen is a relatively nontoxic, nonimmunologic and biolegically nonreactive biomaterial, some side reactions have been reported. We report herein a case of cutaneous side reaction to collagen implantation in a 38-year-old female. The patient presented with puritic, irritating, multiple, erythematous nodules on both the temporal and interorbital area, which had been observed since 1 day after collagen(KOKEN ATELOCOLLA-GEN IMPLANT-Japan) implantation. Histopathologic findings showed dense infiltration of acute and chronic inflammatory cells in the dermis, especially the perivascular and periadnexal area. (Kor J Dermato 1994; 32(1): 134-138)