Background <p>This study aims to validate the suitability of the Inventory of Depressive Symptomatology Self-Report (IDS-SR) for evaluating mood disorders in older adults with subjective cognitive decline (SCD) and mild cognitive impairment (MCI).</p> Methods <p>A total of 1670 participants aged ≥ 50 years were included (531 males; mean age 65.79 ± 7.39 years). Construct validity of the IDS-SR was evaluated using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). Criterion validity was examined using Pearson correlation analyses between IDS-SR scores and scores on the Hamilton Depression Scale (HAMD) and the Hamilton Anxiety Scale (HAMA). Receiver operating characteristic (ROC) curve analysis was conducted to determine the ability of the IDS-SR and its subscales to distinguish mood disorders in SCD and MCI. Cronbach’s α and the intraclass correlation coefficient (ICC) were employed to assess the reliability of the scale.</p> Results <p>The EFA demonstrated that the major factors explained 47.722% of the total variance. The CFA confirmed a three-factor model of the IDS-SR and indicated good construct validity. The fit indices were as follows: chi-square/degree of freedom (<i>χ</i>²/<i>df</i>) = 3.316, root mean square error of approximation (RMSEA) = 0.054, goodness of fit index (GFI) = 0.945, adjusted goodness-of-fit index (AGFI) = 0.928, comparative fit index (CFI) = 0.921, incremental fit index (IFI) = 0.922, and Tucker-Lewis index (TLI) = 0.908. The total Cronbach’s α was 0.839. The ICC for the total scale was 0.952.</p> Conclusions <p>The IDS-SR scale is a reliable and valid screening tool for detecting mood disorders in older adults with SCD and MCI. This study provides the first validation of the scale in this population.</p>