We used a retrospective data mining approach to explore the association between serum amiodarone (AMD) and N-desethylamiodarone (DEA) concentrations and thyroid-related hormone levels. Laboratory data sets from January 2012 to April 2016 were extracted from the computerized hospital information system database at the National Cerebral and Cardiovascular Center (NCVC). Data sets that contained serum AMD and DEA concentrations and thyroid function tests, including thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3), were analyzed. A total of 1831 clinical laboratory data sets from 330 patients were analyzed. Data sets were classified into five groups (euthyroidism, hyperthyroidism, subclinical hyperthyroidism, hypothyroidism, and subclinical hypothyroidism) based on the definition of thyroid function in our hospital. Most abnormal levels of thyroid hormones were observed within the therapeutic range of serum AMD and DEA concentrations. The mean DEA/AMD ratio in the hyperthyroidism group was significantly higher than that in the euthyroidism group (0.95 +/- 0.42 vs. 0.87 +/- 0.28, p = 0.0209), and the mean DEA/AMD ratio in the hypothyroidism group was significantly lower than that in the euthyroidism group (0.77 +/- 0.26 vs. 0.87 +/- 0.28, p = 0.0038). The suppressed TSH group (0.98 +/- 0.41 vs. 0.87 +/- 0.28, p < 0.001) and the elevated FT4 level group (0.90 +/- 0.33 vs. 0.84 +/- 0.27, p = 0.0037) showed significantly higher DEA/AMD ratios compared with normal level groups. The elevated TSH group showed a significantly lower DEA/AMD ratio compared with the normal group (0.81 +/- 0.25 vs. 0.87 +/- 0.28, p < 0.0001). High and low DEA/AMD ratios were associated with AMD-induced hyperthyroidism and hypothyroidism, respectively. The DEA/AMD ratio may be a predictive marker for AMD-induced thyroid dysfunction.