Background: CD163⁺ macrophages (MΦ) infiltrate malignant tissue of breast cancer patients (BrCa) and suppress immunity, through a Th2 microenvironment characterized by high numbers of CD4⁺ and low numbers of CD8⁺ T-cells. We examined the associations between immune cell counts and clinicopathological characteristics. Methods: Serial sections of 59 paraffin-embedded BrCa tissues were immunohistochemically analyzed for the presence of total MΦ, their CD163⁺ subpopulation, helper and cytototoxic T-cells by antibodies to CD68, CD163, CD4, and CD8 markers, respectively. Cells were counted in the intratumoral and peritumoral compartments by two independent observers, and expressed as number of cells for high power field. The medical records of the patients were retrospectively evaluated for various clinicopathologic parameters. Statistical analyses were performed by Tukey’s multiple comparison tests and/or t-tests, or Spearman's correlation test. Results: Highly significant associations were found between the occurrence of CD163⁺ MΦ cells and CD4⁺ (p<0.0001) or CD8⁺ (p=0.0005) T-cells as well as between total CD68⁺ MΦ and CD4⁺ T-cells (p=0.01), detected intratumorally. Importantly, intratumoral CD68⁺ MΦ were positively correlated to relapse (p=0.003), and negatively correlated to survival (p=0.01) in patients treated only with chemotherapy (n=19). Among patients treated with both chemotherapy and hormonal therapy (n=18), relapse was positively associated with peritumoral CD163⁺ MΦ (p=0.04) and negatively with intratumoral CD163⁺ MΦ (p=0.03). The grade of the disease was correlated with the number of total CD4⁺ T-cells peri- and intratumorally (p<0.05), while the CD4⁺ peritumoral population was also associated with nodal disease (p=0.03). Moreover, a positive correlation was revealed between CD8⁺peritumoral T-cells and p53 intense staining (p=0.01). Conclusions: Our study provides evidence that tumor associated macrophages, and specifically their CD163⁺ subpopulation may serve as significant prognostic factors in BrCa, and supports the need for analysis also in terms of localization rather than solely incidence of infiltrating cells in the tumor tissue.