Anxiety affects social, economic, and physical aspects of daily life in patients with AIDS. Therefore, it is necessary to take preventive measures and design plans to maintain their general health. The present study was the first comprehensive systematic literature review research that examined the worldwide prevalence rate of anxiety in patients with AIDS. We searched for papers published in the English language in the major databases including Embase, PubMed, Web of Science, Scopus, Cochrane, and Google Scholar from 2000 to October 2018. There were 40 studies which found to be eligible. These studies were independently evaluated and the collected data were entered in a data extraction form, which was then analyzed by two authors and a third author if necessary. Der Simonian-Laird model was used to estimate the prevalence rate on a Forest plot at the interval confidence of 95%. The total sample size was 24111, and the total number of people with anxiety was 5546. The results based on the random-effects model showed that the rate of anxiety prevalence in the patients was 25% (CI: 95%, 21% -30%) with heterogeneity of 97.9% and a significance level of p<0.001. The South America continent with a prevalence of 38% (95% CI, 34%-42%) had the highest anxiety prevalence rates and Africa with 19% (95% CI, 12% -29%) had the lowest anxiety prevalence rates. Based on findings, the prevalence of anxiety in developed countries was partially higher than in underdeveloped countries and the obtained mean in the present study. It can be a significant point for policymakers. Therefore, WHO and the world community should have special plans for these countries.