BACKGROUND: Greenlanders have a lower rate of cardiovascular mortality and morbidity than Danes, possibly due to lower blood pressure. However, 24-h blood pressure has never been measured in Greenlanders. The aim of this study was to compare the 24-h blood pressure of Greenlanders and Danes, and to analyse the influence of Arctic food and lifestyle on blood pressure. METHODS: Four groups of healthy subjects were recruited for the study. Group I: Danes in Denmark consuming European food; group II: Greenlanders in Denmark consuming European food; group III: Greenlanders in Greenland consuming mainly European food; and group IV: Greenlanders in Greenland consuming mainly traditional Greenlandic food. All subjects underwent a physical examination, laboratory screening of blood and urine samples, and completed a questionnaire on diet, physical activity, smoking status, intake of alcohol, liquorices, vitamins and minerals. Twenty-four-hour blood pressure was measured. RESULTS: It was found that 24-h diastolic blood pressure was lower in Greenlanders than in Danes for the whole 24-h period and during both day and night-time, whereas systolic blood pressure was the same (mean 24-h blood pressure with 95% CI: Danes 123/75 mmHg (120/73-127/77), Greenlanders 122/ 69 (119/68-124/70)). Among Greenlanders, blood pressure increased with age and male gender, and systolic blood pressure increased with body mass index (BMI). No association with diet was found. The difference between the two populations persisted after controlling for age, gender, BMI, outdoor temperature, and lifestyle factors. CONCLUSION: Greenlanders have a lower 24-h diastolic blood pressure than Danes, and it is suggested that genetic factors are mainly responsible for the lower blood pressure level among Greenlanders.