Functional disability is affected by subjective cognitive function, depressive symptoms, and affective temperaments in adults. However, the role of subjective cognitive function as a mediator of affective temperaments in functional disability remains unknown. Therefore, we aimed to determine how subjective cognitive function mediates the effect of affective temperaments on functional disability in adults. A total of 544 participants completed the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Auto questionnaire version (TEMPS-A), the Patient Health Questionnaire-9 (PHQ-9), the cognitive complaints in bipolar disorder rating assessment (COBRA), and the Sheehan Disability Scale (SDS). The association among these instruments was evaluated by multiple regression and covariance structure analyses. The structural equation model showed that the COBRA scores could be predicted directly by the four affective temperaments of the TEMPS-A (cyclothymic, depressive, irritable, and anxious) and indirectly by the PHQ-9. Moreover, the SDS score was predicted directly by these four affective temperaments and indirectly by the COBRA and PHQ-9. Subjective cognitive function mediates the effect of affective temperaments on functional disability in Japanese adults. However, the cross-sectional design may limit the identification of causal associations between the parameters. In the present study, the participants were from a specific community population; therefore, the results may not be generalizable to other communities. © 2020 Toyoshima et al.