Renal insufficiency is common after non-renal organ transplants. The predictors of long-term renal outcomes are not well established. A total of 219 lung and heart-lung transplant recipients surviving more than 6 months after transplantation were studied to determine predictors of time to doubling of serum creatinine and end-stage kidney disease (ESKD) with death as a competing risk. Median follow-up was 79 months (range 9-222 months). Baseline estimated glomerular filtration rate (GFR) was 96.3+/-34.5 mL/min/1.73 m2. One hundred twenty-two recipients (55%) doubled their serum creatinine, 16 (7.3%) progressed to ESKD and 143 (65%) died. The majority of recipients who survived >6 years had a GFR<60 mL/min at both 1 and 7 years. Most of the loss of renal function occurred in the first year post-transplant. Older age at transplant, lower GFR at 1 month and cyclosporine use in the first 6 months predicted shorter time to doubling of serum creatinine when death was handled as a competing risk. Based on this prevalence data and using GFR decay and death as study endpoints, we offer sample size estimates for a prospective, interventional trial that is aimed at slowing or preventing the progression of kidney disease.