Objectives Stigma compounds the burden experienced by family members of those with a mental illness. This study aimed to examine burden experienced by carers of people with schizophrenia or affective disorders and to explore the relationship between carer burden and stigma. Method A cross sectional descriptive study was conducted with patient-carer dyads involving 67 patients diagnosed with schizophrenia and 51 diagnosed with affective disorder. Carers completed the Zarit Burden Interview (short version) and stigma was measured using the Stigma Scale and the Internalised Stigma of Mental Illness Scale. Results Carer burden was significantly higher for schizophrenia than affective disorders. Female carers experienced significantly higher burden than male carers. Diagnosis, gender of carer and stigma predicted 22% of the variance in carer burden, with gender identified as a significant predictor. Conclusions Reducing stigma related to disclosure of mental illness in carers has the potential to reduce carer burden.