Objective: We aimed to elucidate the ameliorative effect of hydrogen sulfide (H2S) on endothelium-dependent relaxation disturbances via peroxisome proliferator-activated receptor delta/endothelial nitric oxide synthase (PPAR delta/eNOS) pathway activation in hypertensive patients and rats. Methods: Renal arteries were collected from normotensive and hypertensive patients who underwent nephron-sparing surgery. Renal arteries from 37 patients were cultured with or without sodium H2S (NaHS) 50 mu mol/l. The rats were randomly divided into four groups: Sham; Sham+NaHS, two kidneys; one clipped (2K1C); and 2K1C+NaHS. Mean arterial pressure was measured by tail-cuff plethysmography. A microvessel recording technique was used to observe the effect of NaHS on endothelium-dependent relaxation. Plasma H2S concentrations were detected using the monobromobimane method. Real-time PCR and western blotting were used to assess mRNA and protein levels of AT1, cystathionine gamma-lyase, PPAR delta, and phosphor-eNOS. Laser confocal scanning microscopy measured intracellular NO production in human umbilical vein endothelial cells. Results: NaHS improved endothelial function in hypertensive humans and rats. The 20-week administration of NaHS to 2K1C rats lowered the mean arterial pressure. In human umbilical vein endothelial cells, NaHS improved the AngII-induced production of NO. NaHS upregulated PPAR delta expression, increased protein kinase B (Akt) or adenosine monophosphate kinase-activated protein kinase (AMPK) phosphorylation, and enhanced eNOS phosphorylation. A PPAR delta agonist could mimic the ameliorative effect of NaHS that was suppressed by PPAR delta, AMPK, or Akt inhibition. Conclusion: H2S plays a protective function in renal arterial endothelium in hypertension by activating the PPAR delta/PI3K/Akt/eNOS or PPAR delta/AMPK/eNOS pathway. H2S may serve as an effective strategy against hypertension.