Glucose ingestion-induced hyperglycemia has been known to induce inflammation, which is related to the pathogenesis of diabetic complications. To examine acute gene expression responses to physiological oral glucose ingestion in human circulating leukocytes, we conducted a microarray study of human circulating leukocytes sampled before, 1 h after, and 2 h after glucose ingestion in community-based participants without previous histories of diabetes (n = 60). Ingestion of 75 g glucose successfully induced acute hyperglycemia (glucose concentration 91.6 ± 5.3 mg/dl for fasting and 180.7 ± 48.5 mg/dl for 1 h after glucose ingestion). Oral glucose ingestion significantly increased the expressions of 23 genes and decreased the expressions of 13 genes [false discovery rate (FDR) P value <0.05]. These genes are significantly involved in immunity by way of natural killer cell-mediated immunity, granulocyte-mediated immunity, and the cytokine-mediated signaling pathway (FDR P value <0.05). The present study demonstrated 36 genes that showed acute gene expression change in human leukocytes within 1 h after glucose ingestion, suggesting that leukocytes participate in the inflammatory process induced by acute hyperglycemia. We believe that these results will provide some basic insight into the role of leukocytes in hyperglycemia-induced inflammation and the pathogenesis of diabetic complications.