). Progression was defined as a change in albuminuria to a higher level.Results. Progression occurred in 21 patients. Progressors had shorter mean telomere length (8.1 ± 0.7 kb, mean ± SD; P = 0.017) and higher percentage of short telomeres (32.0 ± 8%, P = 0.002) than nonprogressors (8.5 ± 0.7 kb and 27 ± 7.2%, respectively). Thus, both shorter telomeres (HR = 0.190, 95%CI 0.065-0.558, P = 0.0025) and higher proportion of short telomeres (HR = 1.115, 1.039-1.195, P = 0.0023) were independent predictors of diabetic nephropathy. Telomere length was not associated with the degree of albuminuria and was not different in patients with type 1 diabetes compared with healthy controls.Conclusions. Short telomeres are independent predictors of progression of diabetic nephropathy in patients with type 1 diabetes.