The association between masked hypertension and metabolic syndrome (MS) or insulin resistance is unclear. We investigated an untreated nationwide population sample (n = 1582, age 44-74 years). Duplicate office blood pressure (BP) measurements were taken on one visit and duplicate morning and evening home measurements were taken for 7 days. Masked hypertension was defined as office BP < 140/90 mm Hg with home BP ⩾ 135/85 mm Hg. Logistic regression analysis was used to determine the association between masked hypertension and metabolic risk factors. Age- and gender-adjusted odds ratios for metabolic disorder were 2.89 (1.87-4.47), 2.93 (2.15-3.97) and 1.68 (1.05-2.70) in white-coat hypertension, 3.39 (2.00-5.76), 3.86 (2.61-5.72) and 2.77 (1.63-4.70) in masked hypertension, and 7.38 (5.19-10.49), 6.45 (4.92-8.46) and 4.27 (3.00-6.08) in sustained hypertension using European Group for the Study of Insulin Resistance, harmonised MS and homeostasis model assessment of insulin resistance above the 80th percentile criteria. When home BP was used to define MS, masked hypertension moved close to sustained hypertension. The association between masked hypertension and metabolic disorders was related to home BP, body mass index and waist circumference. In conclusion, home BP appears to be a useful method to assess the risk of metabolic disorder. Masked hypertensives would benefit from the use of home BP in the definition of MS.