The objective of this study was to determine both the prevalence of white-coat effect and white-coat hypertension (WCH) and which selected clinical variables were predictors of WCH. A total of 2462 patients underwent ambulatory blood pressure monitoring either in borderline hypertension (group 1) or for assessment of antihypertensive treatment (group 2) or for hypotension (group 3). In the overall population 33.0% of patients showed WCH, 32.8% in group 1 and 37.0% in group 2. In multivariate analysis, sex and grade of hypertension were independent predictors of WCH in groups 1 and 2.