The impact of pretransplant overweight/obesity was analyzed in a group of 268 consecutive primary pancreas renal transplant recipients. Obesity was defined as body mass index (BMI) greater than 27 kg/m2. BMI was available for 240 of the 268 patients. A total of 88% (212/240) of the patients had a BMI < or = 27 and 28/240 (12%) had BMI > 27. There were no significant differences in age, sex, or race between obese and nonobese patients. The incidence and degree of posttransplant hypertension, weight gain, increase in BMI, and hyperlipidemia did not differ on the basis of pretransplant BMI. Serum creatinine at one year posttransplant was slightly increased in obese patients, but the increase was not statistically significant. Cumulative prednisone dose (mg/kg) as well as cyclosporine (CsA) dose (mg/kg) at one year was not significantly different between obese and nonobese patients. However, there was a marginally significant negative correlation between BMI and one-year cumulative (mg/kg) prednisone dose (P = .06). Types and frequency of posttransplant complications were similar between obese and nonobese patients, although there was a slightly higher incidence of wound related complications in obese patients (11% vs. 6.8%) (P = NS). There was no difference in the frequency of acute rejection episodes in obese and nonobese patients. Actuarial patient survival was comparable between patients with BMI < or = 27 versus those with BMI > 27 (P = .10). However, actuarial graft survival, both pancreas and renal, were significantly decreased in patients with BMI > 27 (P = .029). The decrease in pancreas and kidney graft survival in obese patients could not be attributed to decreased "early" patient survival, increased incidence of perioperative or postoperative complications, differences in hypertension, acute rejection episodes, serum lipids, or immunosuppression dosage. The most common causes of graft loss were rejection and patient death in both obese and nonobese patients. After three years posttransplant, the decreased pancreas and renal graft survival in obese patients corresponded to decreased patient survival. The most common cause of patient death was cardiovascular complications in both obese and nonobese PKT recipients.