Objective: Sodium-glucose cotransporter-2 inhibitor (SGLT2i) treatment had the effect of reducing blood pressure (BP) and cardiovascular events in recent mega-scale trials, but the effects on BP circadian rhythm remained unclear. The present study aimed to determine the nocturnal antihypertensive effect of SGLT2i compared with dipeptidyl peptidase-4 inhibitor (DPP-4i) in patients with type 2 diabetes and hypertension. Research Design 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: Changes in both nighttime and daytime SBP were significantly reduced in the Luseo group compared with the DPP-4i group (nighttime, −4.0±11.4 vs. 3.6±10.7 mmHg, P=0.01; daytime, −4.4±10.9 vs. 3.7±11.9 mmHg, P=0.01). Similarly, nighttime pulse rate (PR) was significantly reduced in the Luseo group compared with the DPP-4i group (−2.0±4.8 vs. 0.9±4.8 bpm, P=0.03). Abnormal BP circadian rhythms (non-dipper and riser types) were significantly decreased in the Luseo group (56.7% to 36.6%, P<0.05). Conclusions: Switching from DPP-4i to luseogliflozin decreased not only daytime but also nighttime SBP and PR, and improved BP circadian rhythm. These improvements could be some of the factors involved in the cardiovascular event suppression observed with SGLT2i therapy. Disclosure R. Hashimoto-kameda: None. K. Cho: None. H. Nomoto: None. A. Nakamura: Research Support; Self; Boehringer Ingelheim International GmbH, Kissei Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation, MSD K. K., Taisho Pharmaceutical Co., Ltd. K. Omori: None. S. Kawata: None. H. Kameda: None. T. Atsumi: Research Support; Self; Alexion Pharmaceuticals, Inc., Astellas Pharma Inc., Bristol-Myers Squibb Company, Chugai Pharmaceutical Co., Ltd., Daiichi Sankyo, Eisai Co., Ltd., Eli Lilly Japan K. K., Gilead Sciences, Inc., Mitsubishi Tanabe Pharma Corporation, Otsuka Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co., UCB Japan Co. Ltd., Speaker’s Bureau; Self; AbbVie Inc., Astellas Pharma Inc., Chugai Pharmaceutical Co., Ltd., Eli Lilly Japan K. K., Mitsubishi Tanabe Pharma Corporation, Pfizer Inc., Takeda Pharmaceutical Co., UCB Japan Co. Ltd. H. Miyoshi: Research Support; Self; Abbott Japan Co., Ltd., Astellas Pharma Inc., Daiichi Sankyo, Eli Lilly Japan K. K., Kowa Company, Ltd., Mitsubishi Tanabe Pharma Corporation, Nippon Boehringer Ingelheim Co. Ltd., Novo Nordisk Pharma Ltd., Ono Pharmaceutical Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Speaker’s Bureau; Self; Astellas Pharma Inc., Eli Lilly Japan K. K., Kowa Company, Ltd., Mitsubishi Tanabe Pharma Corporation, MSD K. K., Nippon Boehringer Ingelheim Co. Ltd., Novo Nordisk Pharma Ltd., Ono Pharmaceutical Co., Ltd., Sanofi K. K., Sumitomo Dainippon Pharma Co., Ltd. Funding Taisho Pharmaceutical Co., Ltd.