Background: 5-year survival of patients with resectable colorectal liver metastases is 25-40%. Mechanisms of disease progression are heterogenous and do not follow a clearly defined pathway from genotype to phenotype. In stage I-III colorectal cancer (CRC), patients with high tumor stroma exhibit poor prognosis, while those with high immune cell infiltrate do well following resection. We hypothesise that stromally-dense phenotypes lead to T cell exclusion, myeloid cell accumulation and aggressive metastatic progression. Here, we examine relationships between histological tumor phenotype, cellular infiltrate and outcomes in metastatic CRC. Methods: A unique cohort of synchronously resected primary CRC and matched liver metastases (n = 46) were assessed for immune cell infiltration (CD3, CD4, CD8, CD68, CD66b), inflammatory signalling (CXCR2, PDL-1, MMP9) and hypoxia (CAIX) using immunohistochemistry. Tumors were phenotypically subtyped using immune infiltrate (Klintrup-Makinen Grade (KM)), stromal invasion (tumor-stroma percentage (TSP)) and proliferation (Ki67). Results: Phenotypic subtype of primary tumors was predictive of metastatic subtype (rho = 0.522, p = 0.003). Immune phenotypes were associated with good prognosis and stromal phenotypes with poor prognosis (p = 0.004). Infiltration of macrophages and granulocytes associated with poor outcomes (p = 0.018) and increased CXCR2 expression (p = 0.03) at both sites. Increased CXCR2+ cells and macrophages at both sites associated with stromal phenotype (p = 0.02), tumour budding (p = 0.002), low KM grade (p = 0.05) and poor prognosis (p = 0.002). Macrophage and MMP9 levels increased in metastases compared to primary tumour, but no changes were seen in lymphocyte infiltration, CXCR2 and CD66b. Conclusions: Density of immune cell infiltrate, in the primary and metastatic niche, conferred good prognosis. In contrast, stromal, myeloid rich tumors convey poor prognosis. This clinically relevant and histologically efficient process permits segregation of disease and supports further study of relationships in the tumour microenvironment of CRC in the context of chemotherapy to better target therapeutics to individual patients.