This work sought to identify leukocyte subpopulations in the uterus of sheep that change with stage of the estrous cycle and Chlamydia psittaci infection. The proportions of mononuclear leukocytes were compared using a panel of ten monoclonal antibodies and flow cytometry. CD45RA\sp+γδTcR\sp+ lymphocytes were significantly higher in uterine cell suspensions from ewes in estrus (32.01 ± 4.66%) compared to diestrus (13.73 ± 2.26%, p = 0.0060). Similarly, CD8\sp+γδTcR\sp+ cells in the uterus of ewes in estrus were also significantly higher (35.06 ± 5.25%) compared to diestrus (15.60 ± 2.29%, p = 0.0288). Mononuclear leukocyte subpopulations in uterine cell suspensions from ewes in estrus were compared approximately 60 days (newly infected) or at least three years (chronically infected) following experimentally-induced C. psittaci abortion. CD8\sp− γδTcR\sp+ cells were significantly higher in cell suspensions from the uterus of chronically infected ewes (21.97 ± 16.55%) compared to newly infected ewes (1.62 ± 0.29%, p = 0.0223) or controls (2.36 ± 0.72%, p = 0.0264).