BACKGROUND: Comorbidity is very common among patients with cancer. Multidisciplinary team meetings (MDTs) are increasingly the context within which cancer treatment decisions are made internationally. Little is known about how comorbidity is considered, or impacts decisions, in MDTs. METHODS: A systematic literature review was conducted to evaluate previous evidence on consideration, and impact, of comorbidity in cancer MDT treatment decision-making. Twenty-one original studies were included. RESULTS: Lack of information on comorbidity in MDTs impedes the ability of MDT members to make treatment recommendations, and for those recommendations to be implemented among patients with comorbidity. Where treatment is different from that recommended due to comorbidity, it is more conservative, despite evidence that such treatment may be tolerated and effective. MDT members are likely to be unaware of the extent to which issues such as comorbidity are ignored. CONCLUSIONS: MDTs should systematically consider treatment of patients with comorbidity. Further research is needed to assist clinicians to undertake MDT decision-making that appropriately addresses comorbidity. If this were to occur, it would likely contribute to improved outcomes for cancer patients with comorbidities