The aim of the present study was to compare the ambulatory blood pressure levels in mild (stage 1) hypertensive women using oral contraceptives and respective values in nonusers of oral contraceptives with similar office blood pressure. The study group consisted of 24 mild hypertensive patients taking low dosage estrogen-progestogen oral contraceptives. Seventy women of similar age and body mass index who had never used oral contraceptives served as a control group. Both daytime and nighttime systolic blood pressure values were significantly higher in oral contraceptive users. There was an average 8.3 mm Hg difference (95% confidence interval, 3.0 to 13.7 mm Hg; P = .003) for the daytime and 6.1 mm Hg difference (95% confidence interval, 0.4 to 11.8 mm Hg; P = .04) for the nighttime. No significant differences in ambulatory diastolic blood pressure between the two groups were found. These data provide evidence that hypertensive oral contraceptive users with the same office blood pressure as that in hypertensive noncontraceptive users have a significantly higher ambulatory systolic blood pressure. Our results support the opinion that alternative methods of contraception should be considered for hypertensive women in place of oral contraceptives.