To identify pre-pregnancy risk factors for diabetes in pregnancy among a cohort of Australian Indigenous women. Data on 1,009 Indigenous women of childbearing age who participated in a 1998-2000 health screening program in far north Queensland were linked to Queensland hospitalisations data. Women who attended hospital after their health check for a pregnancy-related condition were identified. The data on women who were hospitalised for birth were also linked to Queensland perinatal data. Of 220 women who gave birth, 23 had diabetes in the pregnancy following their health check. A strong predictor of having a subsequent pregnancy affected by diabetes was suboptimal glucose control before conception. The presence of the metabolic syndrome predicted over a threefold increase in risk among non-diabetic women after adjustment for age and ethnicity (PR, 3.50; 95% CI, 1.54-8.00). For each 1-cm increase in waist circumference, there was an age-adjusted increase in risk of 4% for diabetes in pregnancy (1.04; 1.01-1.06). For each 1-mmHg increase in blood pressure (systolic and diastolic), there was an age-adjusted increase in risk of 3% (1.03; 1.01-1.05 and 1.03; 1.00-1.07, respectively). Associations between hypercholesterolaemia and dyslipidaemia and diabetes in the subsequent pregnancy were diminished after adjustment for age and ethnicity. The risk for women with "hyper-triglyceridaemic waist" phenotype before pregnancy was diminished by adjustment for age, ethnicity and baseline fasting glucose. Alcohol intake, smoking, level of physical activity and red cell folate showed little effect. Identification of women at particularly high risk for future diabetes in pregnancy, given their pre-pregnancy health, is important so that they can manage their risks and where overweight or obesity is a factor, interventions aimed at weight management should be implemented.