Sodium-glucose cotransporter-2 inhibitor (SGLT2i) reduces clinic blood pressure (BP), but the effects on BP circadian rhythm remain unclear. The present study aimed to determine the nighttime antihypertensive effect of SGLT2i compared with dipeptidyl peptidase-4 inhibitor (DPP-4i) in patients with type 2 diabetes and hypertension. Materials and Methods: In this randomized, open-label, parallel-group trial, patients treated with DPP-4i were either switched to luseogliflozin 2.5 mg/day (Luseo group; n = 30) or continued DPP-4i (DPP-4i group; n = 26). The patients undertook 24-h ambulatory BP monitoring before and 8 weeks after the group allocation. The primary endpoint was mean change in nighttime systolic BP (SBP).Results: Nighttime SBP, as well as daytime SBP, was significantly reduced in the Luseo group compared with the DPP-4i group (nighttime, À4.0 ± 11.4 vs. 3.6 ± 10.7 mmHg, P = 0.01; day-