Individuals with morbidity, experience worse breast cancer outcomes compared to those without. This meta-analysis assessed the impact of morbidity on breast cancer screening attendance and subsequent early detection (PROSPERO pre-registration CRD42020204918). MEDLINE, PsychInfo and CINAHL were searched. Included articles published from 1988 measured organised breast screening mammography attendance using medical records by women with morbidity compared to those without.. Morbidities were assigned to nine diagnostic clusters. Data were pooled using random-effects inverse meta-analyses to produce odds ratios (OR) for attendance.. 25 study samples (28 articles) were included. Data were available from 17,755,075 individuals including at least 1,408,246 participants with one or more conditions;16,250,556 had none. Individuals with any morbidity had lower odds of attending breast screening compared to controls (k=25,OR=0.76[95% CI 0.70-0.81],p=<0.001,I2=99%). Six morbidity clusters had lower odds of attendance. The lowest were for neurological, psychiatric and disability conditions; odds ratios ranged from 0.45-0.59 compared to those without. Morbidity presents a clear barrier for breast screening attendance, exacerbating health inequalities and, includes a larger number of conditions than previously identified. Consensus is required to determine a standardised approach on how best to identify those with morbidity and determine solutions for overcoming barriers to screening participation based on specific morbidity profiles.