BACKGROUND It has been hypothesized that genomic instability related to telomere dysfunction may contribute to carcinogenesis. There is some evidence from case-control studies suggesting that short leukocyte telomere length may be associated with an increased risk of renal cell carcinoma (RCC); however, this association has not been investigated prospectively. METHODS We conducted a nested case-control study (209 cases, 410 controls) of RCC risk in relation to prediagnostic leukocyte telomere length in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. ORs and 95% confidence intervals (CI) were estimated using conditional logistic regression. RESULTS Leukocyte telomere length was not significantly associated with future risk of RCC (highest quartile vs. lowest: OR, 0.8; 95% CI, 0.5-1.5; Ptrend = 0.6). Analyses stratified by sex, age, and time from blood collection to RCC diagnosis were similarly null. CONCLUSIONS The results of this study, to our knowledge the first prospective investigation of its kind, do not support an association between prediagnostic leukocyte telomere length and risk of RCC. IMPACT In contrast to some earlier reports, our findings add to the evidence that leukocyte telomere length is not a biomarker of risk related to the etiology of RCC.