: Atrial fibrillation (AF) often coexists with hypertension in the elderly and multiplies the risk of stroke and death. Blood pressure (BP) measurement in patients with AF is difficult and uncertain and has been a classic exclusion criterion in hypertension clinical trials leading to limited research data. This article reviews the evidence on the accuracy of BP measurement in AF performed using different methods (office, ambulatory, home) and devices (auscultatory, oscillometric) and its clinical relevance in predicting cardiovascular damage. The current evidence suggests the following: (i) Interobserver and intra-observer variation in auscultatory BP measurement is increased in AF because of increased beat-to-beat BP variability and triplicate measurement is required; (ii) Data from validation studies of automated electronic BP monitors in AF are limited and methodologically heterogeneous and suggest reasonable accuracy in measuring SBP and a small yet consistent overestimation of DBP; (iii) 24-h ambulatory BP monitoring is feasible in AF, with similar proportion of errors as in individuals without AF; (iv) both auscultatory and automated oscillometric BP measurements appear to be clinically relevant in AF, providing similar associations with intra-arterial BP measurements and with indices of preclinical cardiac damage as in patients without AF, and predict cardiovascular events and death; (v) Screening for AF in the elderly using an AF-specific algorithm during routine automated office, home or ambulatory BP measurement has high diagnostic accuracy. In conclusion, in AF patients, BP measurement is important, reliable, and clinically relevant and should not be neglected in clinical research and in practice.