A study of 1000 patients attending a diabetes referral centre in Amman, Jordan, identified factors associated with good glycaemic control, as measured by glycosylated haemoglobin (HbA1c) levels. Glycaemic control improved significantly between the first clinic visit and at 12-months follow-up. The proportion of patients with extreme HbA1c (> or = 10%) decreased from 15.3% to 6.0% after 12 months. The percentage of patients with optimal control (HbA1c < 7%) increased from 25.4% at the first visit to 27.5% at 12-month follow-up. Multivariate regression showed that low body mass index, shorter duration of diabetes and higher baseline HbA1c were related to reductions in HbA1c between the first and 12-month visits.