Background: Aging comes up with alterations in the immune response that renders increased susceptibility to infectious diseases, cancer, autoimmunity, and inflammation-associated disorders. This decline in immune function has been termed as immunosenescence, yet its mechanisms are still poorly understood. Experimental approaches of adaptive immunity, particularly in T cells, have been the main focus of immunosenescence research. This systematic review evaluates and discusses T cell markers related to immunosenescence. Objective: Determine the best flow cytometry markers of an immunosenescence associated phenotype in circulating T cells. Methods: We systematically searched in PubMed/MEDLINE, EBSCO, and BVS for original articles studying healthy humans of two age groups, 18-44 and over 60 years old. We then followed the Chocharne methodology guidance and synthesized the data in qualitative descriptions and by quantitative random effects model meta-analysis due to extensive heterogeneity. Results: 36 studies of the last 20 years were included for qualitative analysis and four of them allowed us to perform meta-analysis. Significantly decreased naive T cell subset in older adults compared to younger adults was attested. Primary markers used to identify senescent cells were the loss of CD28 and increased expression of CD57 and KLRG1 in terminally differentiated memory subset in older adults. Moreover, we found an increase in proinflammatory cytokines and decreased telomere length in older adult T cells. It was not possible to perform quantitative synthesis concerning cell markers, cytokines, and telomere length because significant variations between groups, attributable to differing protocols and unreported measurements, generated high risk of bias. Conclusions: Heterogeneity among studies regarding data report and measurement techniques and high risk of bias were major impediments for performing robust statistical analyzes.