Resistant hypertension (RH) is a concept that currently goes beyond the classical definition of blood pressure >= 140/90 mmHg in subjects receiving three or more drugs of different classes at maximally tolerated doses. Here, we review the clinical relevance of RH and the different types of RH-associated phenotypes, namely refractory hypertension, controlled resistant hypertension, and masked uncontrolled hypertension. We also discuss current drug strategies and future treatments for these high-risk phenotypes.