Aim The aim of this case-control study was to assess the relationship between resistin levels and obesity and insulin resistance in type 2 diabetic patients. Methods The study involved a sample of the Jordanian population that included 140 type 2 diabetic patients and 125 control subjects. Results Serum resistin levels were higher in type 2 diabetic patients compared with the controls ( P < 0.01). Markers of adiposity [body mass index (BMI) and waist circumference (WC)] and insulin resistance, as well as fasting blood glucose, glycated haemoglobin, urea and blood pressure were considerably higher among the studied diabetics than in the controls. When diabetic patients were subdivided into age-group categories of 10-year intervals, resistin levels significantly increased with increased age, with a significant proportion in the group aged > 60 years ( P < 0.01). Similarly, there was a significant association between plasma resistin and blood urea with growing older in diabetic patients. Pearson's analysis revealed positive correlations between plasma resistin and age, urea, creatinine, insulin, BMI, WC, body-fat content and homoeostasis model assessment (HOMA). Furthermore, plasma resistin concentrations were higher in type 2 diabetic obese patients than in non-diabetic obese subjects ( P < 0.01), whereas no such difference was found between overweight and normal-weight controls. Conclusion These results suggest that variations in resistin concentrations are not directly related to susceptibility to type 2 diabetes. However, it may be that resistin plays a role in the pathogenesis of obesity and insulin resistance, both of which could, indirectly, contribute to the development of type 2 diabetes.