['Twenty-four hour ambulatory blood pressure (ABPM) is emerging as a valuable tool to assess blood pressure (BP) changes in children with type 1 diabetes mellitus (DM1). Hypertension (HTN) is an important risk factor for, and may be an important indicator of diabetic nephropathy. Early accurate identification of HTN in DM1 may improve outcomes.', 'To evaluate BP in adolescents with DM1 using 24-hour ABPM, and to identify risk factors associated with abnormal blood pressure.', 'The ABPM of 105 children with DM1 was reviewed. Mean systolic BP (sBP) percentile was determined from the National High Blood Pressure Education Program (NHBPEP) tables. The patients with abnormal sBP were compared to those with normal sBP with respect to age, race, sex, body mass index (BMI) percentile, duration of DM1, average hemoglobin A1c (HbA1c) over the preceding year, and family history of hypertension.', 'Mean sBP was normal in 71%, whereas 23% had pre-hypertension, and 6% had stage 1 hypertension. Those who had abnormal sBP (pre-hypertension and stage 1 hypertension) had higher HbA1c (p = 0.023) and were more likely to be male (p = 0.03) than those with normal sBP.'] Is poor glycemic control associated with abnormal changes in 24-hour ambulatory blood pressure in children and adolescents with type 1 diabetes mellitus?