Objective: Given the reported increased rates of physical morbidity and higher mortality rates among people with severe mental illness (SMI) (schizophrenia and severe mood disorders), with a life expectancy shorter of 15-20 years with respect to the general population, the aim of this paper was to call attention to the problem of cancer in SMI. Methods: We conducted a narrative review of the most significant papers published in the areas of cancer screening, incidence, mortality and palliative care in SMI. Results: Data from the literature confirm disparities in screening (eg, mammography; pap-smear test; colorectal cancer screening) and prevention (eg, clinical breast examination; smoking cessation). The incidence of cancer was found to be variable with a portion of the studies reporting a higher prevalence while others a similar or a lower prevalence of cancer compared to the general population. A lower percentage of patients with SMI received proper cancer treatment resulting in survival after cancer diagnosis significantly worse than people without SMI. Likewise, end-of-life care has been shown to be lacking with poorer levels of physical, psychological and spiritual care. Conclusions: The problems of stigma and discrimination, poorer dignity, poorer health behavior, lack of integration in health-care services for people with SMI needs to be addressed and solved in cancer care. Psycho-oncology has a very specific and mandatory role in integrating the recommendation of the World Health Organization to improve the links between oncology and mental health settings for more specific psycho-oncology programs addressed for this vulnerable segment of the population.