Glycemic conditioning was investigated in four experiments in which insulin was administered to animals in particular stimulus contexts. Both hyperglycemic and hypoglycemic conditioned responses were obtained, with the directionality of the CR dependent upon which environmental complex was used as the CS. These bidirectional glycemic CRs were obtained in both within-Subject and between-Subject conditioning procedures. Additional experiments indicated that the hyperglycemic CR was probably not related to illumination differences between the two conditioning contexts, nor to a differential opportunity for activity in the two conditioning contexts. Several possible reasons for the occurrence of bidirectional glycemic CRs were considered.