An advantage for trichromatic color vision in primates is shown by its presence in many lineages, but little attention has been paid to the potential disadvantages of trichromacy. Most New World monkey species are polymorphic for color vision, with both dichromats and trichromats present within a single population. We tested the foraging ability of trichromatic and dichromatic Geoffroy's marmosets (Callithrix geoffroyi) for colored cereal balls (Kix®) under conditions of red-green color camouflage (orange/green Kix® against an orange/green background) or lack of camouflage (Kix® same color as background) in a naturalized captive setting. In separate experiments designed to test foraging ability at long distances (<6 m)="" and="" short="" distances=""><0.5 m),="" trichromats="" found="" significantly="" fewer="" kix®="" under="" the="" camouflage="" condition="" than="" in="" the="" non-camouflage="" condition.="" in="" contrast,="" there="" is="" no="" difference="" in="" the="" ability="" of="" dichromats="" to="" detect="" color-camouflaged="" versus="" non-camouflaged="" kix®.="" there="" is="" no="" significant="" difference="" between="" dichromats="" and="" trichromats="" for="" either="" camouflaged="" or="" non-camouflaged="" kix®,="" though="" the="" power="" in="" the="" tests="" is="" low="" because="" of="" high="" individual="" variation.="" the="" results="" have="" clear="" implications="" for="" the="" foraging="" strategies="" of="" trichromatic="" marmosets.="" differences="" in="" intensity="" of="" competition="" between="" trichromats="" and="" dichromats="" for="" items="" of="" food="" of="" different="" colors="" in="" relation="" to="" background="" may="" also="" have="" consequences="" for="" the="" foraging="" behavior="" of="">