Anxiety disorder is a psychiatric condition reported in diabetic patients. It is known that hypothalamus–pituitary–adrenal axis activity is increased in these patients and corticosteroids levels are augmented, whereas the anxiolytic actions of diazepam are reduced. The aim of this study was to evaluate the participation of glucocorticoid (GR) and mineralocorticoid (MR) receptors in anxiety in diabetic mice and whether the blockade of these receptors synergizes with diazepam in the diabetic condition, leading to a reduction of anxiety. Diabetes was induced with streptozotocin (STZ) and anxiety-like levels were evaluated on days 5, 15, and 30 after STZ. Independent groups of control and diabetic mice were treated with diazepam (0.25–2.0 mg/kg), RU-486 (12.5–100 mg/kg), spironolactone (12.5–100 mg/kg), or the combination of suboptimal doses of diazepam and MR or GR antagonists. Results showed that STZ increased anxiety-like behavior 15 days after its administration. The response to diazepam was reduced in diabetic mice, whereas GR and MR blockade induced anxiolytic-like effects in these animals. Coadministration of MR or GR antagonists synergized with diazepam to induce anxiolytic-like effects. The results suggest the participation of corticosteroid receptors in the increased anxiety-like response in diabetic mice and that the blockade of these receptors facilitates the effects of diazepam.