The objective of the study was to review published evidence on whether blood pressure levels and the prevalence of hypertension are higher or lower in South Asian adults living in the UK as compared to white populations. A systematic literature review was carried out using MEDLINE 1966-2001, EMBASE 1980-2001, and citations from references. A total of 12 studies were identified. The data showed important differences between studies in terms of age and sex of samples, definition of South Asians (Indian, Pakistani and Bangladeshi) and methods of evaluating blood pressure. Seven studies reported lower mean systolic blood pressures, while seven studies showed higher diastolic pressures in South Asian men compared to white men. In women, six of nine studies showed lower systolic blood pressures, while five reported higher diastolic pressures. For prevalence of hypertension, five of 10 studies reported higher rates in South Asian men than in white men. Two of six studies showed higher prevalence rates in South Asian women. Overall, the most representative sample and up-to-date data came from the Health Survey of England 1999. Both blood pressure and the prevalence data show important differences between South Asian subgroups, yet most studies combined them. The data also showed a geographical variation between London (comparatively high blood pressure in South Asians) and the rest of the UK (comparatively low or similar blood pressure). Bangladeshis had low blood pressure and body mass index (BMI). In other South Asian subgroups, low blood pressure and the low BMI did not always coincide. To conclude, the common perception that blood pressure in South Asians is comparatively high is unreliable-the picture is complex. Overall, blood pressures are similar but there is stark heterogeneity in the South Asian groups, with slightly higher blood pressure in Indians, slightly lower blood pressure in Pakistanis, and much lower blood pressure in Bangladeshis. Variations in study methods, body shape, size and fat, and in the mix of South Asian groups probably explain much of the inconsistency in the results.