Background and Aim: Aging is a biological reality that has its own dynamism. It goes beyond human control and will reduce performance over time due to the accumulation of cellular and molecular damage. The aim of this study was to investigate the effectiveness of working memory rehabilitation on dorsolateral frontal lobe functions in the elderly. Materials and Methods: This was a quasi-experimental study with a pretest-posttest design and a control group. The study population included all elderly people who lived in Bukan Nursing Home from April to July 2019 (N=120). Among these individuals, 30 elderly people were selected by convenience sampling method and then randomly assigned to two experimental and control groups (two groups of 15 people). Stroop Test and CPT Test were taken from the groups in the pretest. Then, working memory rehabilitation based on the Dehn's Model was performed in 18 sessions (60 minutes each session) and after which the posttest was performed again. The data were analyzed by multivariate covariance test according to its assumptions. Results: The findings showed that after performing working memory rehabilitation, in the experimental group, the mean components of incongruent card, congruent card, omission error, commission error, and reaction time decreased, and the mean of interference components and correct detection increased (P<0.001). However, there was no statistically significant difference in the control group. Conclusion:The results showed that working memory rehabilitation can improve information processing speed and sustained attention, and it is recommended that this rehabilitation method can be used to improve the cognitive functions of the elderly.