Resistant hypertension is defined as blood pressure that remains above 140/90 mm Hg despite the concurrent use of optimal dose of 3 antihy- pertensive agents of different classes. Ideally, 1 of these 3 agents should be a diuretic agent. The etiology of resistance hypertension is multi- factorial. Successful treatment requires identification and reversal of lifestyle factors (obesity, dietary salt intake, alcohol intake, lack of adher- ence to prescribed medicines, and interfering substances), and to exclude the presence of pseudoresistance. Once confounding factors have been ruled out, evaluation for potentially treatable secondary causes of hypertension should be considered. Most forms of secondary hyperten- sion are related with adrenal or renal disorders such as primary hyperaldosteronism and renovascular disease. Although, obstructive sleep apnea syndrome is not a typical cause of secondary hypertension, it is commonly present in resistant hypertension. Diagnostic workup and management of resistant hypertension were discussed in different clinical presentations. (Anadolu Kardiyol Derg 2014; 14: 192-5)