Systemic inflammation has been proved to play a crucial role in promoting cancer progression and metastasis in many cancer types, including colorectal cancer (CRC). The aim of the present review was to provide an overview of studies regarding the prognostic value of inflammation-based markers in patients with CRC. A literature search was performed for articles reporting the prognostic value of the Glasgow prognostic score (GPS), modified GPS (mGPS), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) in relation to CRC outcomes. In resectable early-stage CRC, high GPS scores seem significantly associated with cancer-specific survival. It has also been suggested that adjuvant chemotherapy for stage II CRC could improve cancer-specific survival in patients with high GPS scores. In patients with both resectable and unresectable metastatic CRC and a higher GPS score, all studies suggested poorer overall survival. In early-stage and resectable metastatic CRC, the NLR seemed related to overall survival; however, the data for disease-free survival were discordant. In metastatic disease, a possible correlation between a greater NLR and poorer response to bevacizumab has been suggested. Data concerning the prognostic and predictive role of the PLR and LMR in CRC are to date insufficient. In patients with unresectable metastatic disease, inflammation markers can be used to predict the chemotherapeutic outcome and monitor tumor progression. However, further prospective studies might lead to better risk stratification for patients eligible for curative surgery, thus, allowing the restriction of neoadjuvant and adjuvant therapy to patients with high-risk CRC.