Background: Recently, with the advances in the medicine of boosting the immune system, high ability of peptides for the treatment of viral diseases has been proved. By now, there is no effective vaccine against HIV-1 infection. Previous studies confirmed the efficiency of capsid and envelope proteins of papilloma, Herpes and Adeno viruses in new vaccines design. The present study was planned to predict T-cells epitopes from P24 protein by bioinformatics tools and study their effects on lymphocyte proliferation. Methods: To this aim, sequences of 22 peptides corresponding to P24 protein were obtained from NIBSC and have been examined using HLAPred, Propred, SVMHC, SYFPEITHI, and IEDB server. In this experiment, the peptides were prepared at concentrations of 10,100,500 and 1,000 µg/ml. At the end, the selected peptides were tested on the Iranian blood lymphocyte cells (PBMC). Results: The results demonstrated that positive peptides significantly increased lymphocyte proliferation. However the negative peptides did not have any effect on lymphocyte proliferation. Results also showed that p16 and p3 among tested peptides had highest and lowest effects on lymphocytes proliferation respectively. Conclusion: The results of present study confirmed that epitope predictions tools can be reliable alternatives to experimental work.