Objective To investigate the relationship of nonthyroidal illness syndrome (NTIS) and chronic kidney disease (CKD) in the elderly hospitalized patients with type 2 diabetes (T2DM) and to assess the value of NTIS in T2DM prevention and treatment. Methods According to the thyroid function tests, 126 elderly patients hospitalized during October 2012 to September 2014 in our hospital were divided into NTIS group (n＝30) and non-NTIS (NNTIS) group (n＝96). The clinical data such as serum creatinine, urine albumin creatinine ratio (ACR) of the 2 groups were detected and compared. According to the modification of diet in renal disease (MDRD) equation, the diagnosis of renal insufficiency was established when estimated glomerular filtration rate (eGFR) ＜60ml/(min·1.73m2). Results (1) The incidence of NTIS in the 126 patients was 23.81% (30/126). (2) The incidence of renal insufficiency in the cohort was 57.94% (73/126). The incidence of renal insufficiency in NTIS group [76.67%(23/30)] was significantly higher than in NNTIS group [52.08% (50/96); P＝0.017]. (3) The patients in NTIS group were older than those in NNTIS group (P＜0.001). The level of total triiodothyronine (TT3; P＝0.001), total thyroxine (TT4; P＝0.005), free triiodothyronine (FT3; P＜0.001), free thyroxine (FT4; P＝0.036), thyroid-stimulating hormone (TSH; P＝0.012), albumin (ALB; P＜0.001), total cholesterol (TC; P＝0.027), triglycerides (TG; P＝0.034), low-density lipoprotein cholesterol (LDL-C; P＝0.032), eGFR(P＝0.004) and calcium (Ca; P＜0.001) were lower in NTIS group than in NNTIS group. (4) The Spearman univariate correlation analysis showed that NTIS was positively correlated with ACR (P＝0.011), age (P＜0.001) and renal insufficiency (P＝0.001), and was negatively correlated with ALB (P＜0.001) and Ca (P＜0.001). (5) The multivariate logistic regression analysis showed that ALB (OR＝0.246, P＝0.006) and renal insufficiency (OR＝5.346, P＝0.004) were the independent risk factors of NTIS in the elderly patients with T2DM. Conclusion NTIS in the elderly hospitalized patients with T2DM may indicate stage 3 or higher CKD, and may be an independent predictor for high severity and poor prognosis.