Within the last 2 years, major guidelines have been issued from US-based and European organizations that differ in their recommendations for the diagnosis and treatment of hypertension. Experts from both sides of the Atlantic--Paul Whelton, MD, from the United States (Tulane University, New Orleans, Louisiana) and Bryan Williams, MD, from Europe (University College London in England)--discuss the similarities and differences in these guidelines and the basis for the differences. They were interviewed by JAMA editors Greg Curfman, MD, and Ed Livingston, MD.