Both male and female 16-week-old agouti KKAy+/–ApoE–/– mice revealed non-fasted blood glucose levels >250 mg/dl, reflective of diabetes, with greater than 2-fold increase in glucose levels noted in these animals compared to age- and sex-matched non-agouti KKAy–/–ApoE–/–. This evidence concerns the gene APOE and diabetes mellitus.