Adiponectin is an adipose-specific protein with insulin-sensitizing and anti-atherogenic properties. It is not known if pre-transplant plasma adiponectin levels can be used to predict new onset diabetes after transplantation (NODAT). We performed a case-control study to evaluate the potential role of adiponectin as a risk factor for NODAT independent of obesity, and then to find a threshold for identification of high-risk patients. Forty nine patients with NODAT were compared to 49 transplant patients (controls), matched for age, gender, body mass index at the time of transplant, and the calcineurin inhibitor agent used for immuno­suppression. Adiponectin levels were also measured in thirty five healthy subjects with normal renal function. Adiponectin levels were significantly higher in pre-transplant patients compared with healthy subjects (13.9 +/- 5.8 µg/ml vs. 9.5 +/- 4.2 µg/ml; p<0.0001). In multivariate analysis, higher plasma adiponectin level was protective against NODAT (incidence rate ratio 0.86 [95% CI 0.78-0.95], p=0.002). All patients with adiponectin levels ≤ 7 µg/ml (8.2%) developed NODAT. This corresponds to a positive predictive value of 100%. None of the patients with adiponectin values ≥ 22 µg/ml (7.1%) developed NODAT. For a threshold of 10 µg/ml (27.6%), more than one third of patients developed NODAT; the adjusted incidence ratio was 4.29 [95% CI 1.62-11.47] (p=0.004). This study shows that low pre-transplant plasma adiponectin levels are associated with a higher risk for subsequent development of NODAT. These results suggest that a threshold of 10 µg/ml can identify high-risk patients for whom preventive interventions might be employed.