Abstract Body: The presence of lipid-loaded macrophages in the artery wall and kidney characterizes diabetic atherosclerotic cardiovascular disease and diabetic kidney disease, respectively. Monocytes, the precursors of macrophages, can also accumulate lipids; however, whether diabetes directly alters monocytes remains unclear. To test this, we used a mouse model of type 2 diabetes (T2D) driven by homozygous leptin-deficiency and silenced the LDL receptor (LDLR) with an antisense oligonucleotide to induce dyslipidemia. Using unbiased proteomics and RNA sequencing, we show that diabetes profoundly affects circulating non-classical monocytes, leading to upregulation of glucose metabolism pathways and suppression of cholesterol homeostasis pathways, indicative of lipid loading, as well as pathways associated with cell activation and inflammation. Functional analyses confirmed that non-classical monocytes exhibit increased glucose uptake (6azGal uptake using flow cytometry: 10928 ± 841 MFI 6azGal in T2D and 8635 ± 530 in controls, p=0.04, N=7-10) and a lipid-loaded phenotype (intracellular perlipin-2; 4-fold increase in T2D vs controls, p=7.7x10^-7, N=6-8), which was confirmed in two additional mouse models of diabetes. Non-classical monocytes were also more lipid-loaded in individuals with type 2 diabetes (1.4-fold increase in T2D vs healthy individuals, p=7.1x10^-4, N=17-19). Non-classical monocyte lipid loading in diabetes did not correlate with plasma lipids, but rather with blood glucose (r²=0.2, p=0.03, N=23), and in vitro and in vivo exposure to high glucose and diabetes augmented monocyte VLDL binding (2.3-fold increase in DiI-VLDL binding in the mouse model of T2D vs controls, p=6.7x10^-4, N=7-8). Despite hyperglycemia-induced increases in monocyte cell-surface CD36, monocyte CD36 did not influence diabetes-augmented non-classical monocyte lipid loading. We find that non-classical monocytes traffic to the kidney and contribute to a foamy macrophage population in a mouse model of diabetic kidney disease, via a process regulated by CD36 (hematopoietic CD36-deficiency resulted in a 20% reduction in kidney macrophages, p=0.042). Together, these findings suggest that hyperglycemia in diabetes drives the reprogramming of non-classical monocytes, leading to lipid loading and contributing to the accumulation of lipid-loaded macrophages in diabetic kidney disease.