© 2016 The Cochrane Collaboration.Background: Adults with severe mental illness (i.e. schizophrenia or other related psychotic disorders and bipolar disorder) can be at greater risk of cancer than those without severe mental illness (SMI). Early detection of cancer through screening is effective in improving patient outcomes including death. However, people with SMI are less likely than others to take up available cancer screening. Objectives: To determine the effectiveness of interventions targeted at adults with SMI, or their carers or health professionals, and aimed at increasing the uptake of cancer screening tests for which the adults with SMI are eligible. Search methods: We searched the Cochrane Schizophrenia Group's Trials Register (October 25, 2012; December 19, 2014; April 07, 2015; July 04, 2016). Selection criteria: All randomised controlled trials (RCTs) of interventions, targeted towards adults with SMI or their carers or health professionals, to encourage uptake of cancer screening tests for which the adults with SMI were eligible. Data collection and analysis: Two review authors independently screened titles and abstracts and assessed these against the inclusion criteria. Main results: We did not find any trials that met the inclusion criteria. Authors' conclusions: A comprehensive search showed that currently there is no RCT evidence for any method of encouraging cancer screening uptake in people with SMI. No specific approach can therefore be recommended. High-quality, large-scale RCTs are needed urgently to help address the disparity between people with SMI and others in cancer screening uptake.