Human Mucosal Associated Invariant T (MAIT) cells are the predominant innate-like T cell population in circulation and are particularly susceptible to pro-apoptotic stimuli, contributing to chronic viral- and age-related inflammation. Despite evidence demonstrating phenotypic differences between peripheral and tissue-specific MAIT cells, to date, the diversity of the human circulating MAIT cell population is not fully elucidated. Also, ART-suppressed HIV infection and aging are each reported to impact the number of circulating MAIT cells; however, shifts in the MAIT subsets defined by CD4 and CD8 expression in these conditions are unclear. We performed 35‑color spectral flow cytometry on peripheral blood mononuclear cells from participants of our HIV and Aging cohort, which is comprised of individuals with ART-suppressed HIV infection or uninfected controls from younger (<35yo) and older (>50yo) subgroups (N=100). Collected datasets were visualized using opt‑SNE to enable an unbiased and comprehensive assessment of MAIT cell phenotypic signatures. Of all circulating MAIT (Va7.2+CD161+ ) cells, significantly lower frequencies were found in older as compared with younger individuals, with levels similar +/-HIV. A strong negative correlation was identified between MAIT cell frequencies and the number of age-associated co-morbidities present in the cohort participants. Diverse CD45RA, CCR6, NKG2D, CD56, CD45RO, and CD69 expressions were found, and these varied between MAIT subsets that differed in CD4 and CD8 expression. In older individuals, there was an enrichment of CD4+ MAITs compared with younger counterparts, irrespective of HIV status. These results underscore the substantial impact of age on the human peripheral MAIT cell compartment. Future work will involve a comprehensive functional analysis of the MAIT cell subsets that differ in CD4 and CD8 expression to gain insight into the distinct roles of these MAIT factions in the inflammation found with aging.