Context: Acceptance and commitment therapy (ACT) is a cognitive-behavioral psychotherapy method focusing on acceptance and commitment to life values. Objectives: This study aimed to evaluate the effectiveness of the ACT method on the life expectancy (LE) of patients with different diseases. Evidence Acquisition: The present study is a literature review that collects findings from past related studies in the last two decades. For this purpose, the essential and common Medical Subject Headings (MeSH) terms were first identified. Then, the desired MeSH terms were searched in the most reliable and essential international databases, including Google Scholar, Scopus, PubMed, Web of Science, and national databases, including Magiran, SID, Iran doc, etc. First, 265 articles were identified, and then 18 were selected as final studies considering the inclusion and exclusion criteria. Results: The findings of 18 studies were extracted for the present study. Some different types of patients, including those with rheumatoid arthritis, depression, multiple sclerosis, asthma, diabetes, liver transplants, chronic pain, cancer, physical-motor disabilities, drug addiction, and others, were shown to increase LE through the use of the ACT method. The main finding of the present study was that using the ACT method to increase LE in patients with various diseases has a significant effect, which was clearly highlighted in all the selected studies. Conclusions: Based on the findings, ACT is an effective and high-efficiency method in increasing patients' LE. Acceptance and commitment therapy can improve LE, resilience, quality of life, compliance with treatment, and other patient benefits, thus improving the speed of recovery for patients. Therefore, the ACT method, which is a non-pharmacological method, can be used by specialists and clinical psychology experts for different patients.