BackgroundIn recent years, around 30% of all mortalities worldwide has been related to cardiovascular disease (CVD). The most important predictor solution of cardiovascular events is enhancing medication adherence. Meanwhile, the main reason behind development of physical disorders among the elderly is depression. In this regard, the present research was performed to determine the relationship between depression and medication adherence among the elderly suffering from CVD.MethodsA cross‐sectional study was done via an analytical approach on 188 elderlies fulfilling the inclusion criteria. The participants were chosen through convenience nonrandomized sampling from March to July 2022. The data were collected through demographic and healthcare information form plus Madanloo chronic disease medication adherence and geriatric depression scale. The analysis of the data was done by SPSS 26 plus Stata 14.2.ResultsThe mean depression score was 5.6(4.3) and the mean score of medication adherence in the elderlies was 168.03(23.85). The prevalence of depression was higher in women than in men (p = 0.015), and the elderlies differing from heart failure reported the minimum extent of medication adherence. The findings obtained from analysis of variance showed that age, level of education, and monthly level of income were among the effective demographic factors in the extent of depression and medication adherence (p < 0.05). Meanwhile, 26% of changes in medication adherence can be attributed to depression. Further, the results of the multiple linear regression model reported that depression, age, and polypharmacy are among the predictors of medication adherence.Discussion and ConclusionA weak to moderate relationship existed between depression and medication adherence among these elderlies. Given the growing elderly population, the importance of depression, and lack of medication adherence in incidence of CVD events, it is recommended to train the healthcare team to monitor the elderly regarding depression symptoms.