Background: This study was conducted to determine the effect of simple calculation and reading aloud on postoperative cognitive function and depression level in older adults. Method: The study was a randomised controlled experimental study. A personal information form, Mini-Mental State Examination (MMSE) and Geriatric Depression Scale (GDS) were used for data collection. Results: In the evaluation of MMSE and GDS scores of the intervention and control groups 4 weeks after the operation, the differences between the two groups were found to be statistically significant. Conclusion: The results found that simple calculation and reading aloud after surgery had a positive effect on cognitive function and depression level in older people.