Although more than half a century has passed since the discovery of fluoropyrimidines, they are still used in the treatment of many types of cancer, and it is estimated that annually two million patients undergo fluoropyrimidine-based chemotherapy. The toxicity resulting from the use of fluoropyrimidines affects about 30-40% of patients, which in some cases may prove to be lethal. The key player in fluoropyrimidine toxicity is DPD activity, and patients with deficits are more likely to develop significant adverse events. In addition to genotyping DPYD variants associated with DPD deficiency, overexpression of miR-27 has also been shown to be a predictive factor for fluoropyrimidine toxicity. This review aims to relate what we know so far about the involvement of miRNA in fluoropyrimidine toxicity and to open new perspectives in this field.