Many middle-income countries now have a high prevalence of diabetes and need to address the problem of providing care for people with diabetes within limited resources. This study evaluated standards of preventive care in primary settings in three Caribbean countries. We studied case records at 17 clinics in 15 government health centres and 17 private general practitioners' offices in Barbados, Trinidad and Tobago and Tortola (British Virgin Islands). A census of all attenders over a 4 to 7 week period identified 1661 attenders with diabetes mellitus, approximately two-thirds were women with a median age over 60 years. Overall 676/1342 (50%) had 'poor' blood glucose control (> or = 8 mmol l-1 fasting or > or = 10 mmol l-1 random). The proportion with BP > or = 160/95 mmHg or receiving treatment for hypertension was 943/1661 (57%), of whom 781/943 (83%) were prescribed drug treatment. Among those treated for hypertension only 181/781 (23%) had blood pressures < 140/90 mmHg. Surveillance for complications affecting the feet (11%) or eyes (2%) was not performed systematically in any setting. Only 533 (32%) had recorded dietary advice and 79 (5%) had recorded exercise advice in the last 12 months. To begin to address some of these problems at a regional level, we incorporated results from this survey into a series of workshops held in collaboration with health ministries in 10 Caribbean countries, with participants from 13 countries. At these workshops health care workers participated in the process of developing guidelines for diabetes management in primary care. The guidelines have subsequently been widely disseminated through health ministries and non-governmental organizations in the region. Further research is needed to evaluate the effectiveness of this approach, the constraints on diabetes care, and the most cost-effective means of addressing them.