Background: Dementia in late stages affects patients' life like being dependent, malnourished, having psychological and sleep problems. Caregivers face physical, financial, medical, and psychological b urdens and are in need for support to complete caregiving responsibilities. Not all caregivers have the sufficient knowledge regarding how dementia affects the patients. Aim: To determine the burden of caregiving process on caregivers of moderate to severe and severe dementia patients, the type of support and knowledge that caregivers need during this process Methods: a cross -sectional study involving 101 caregivers of moderate to severe and severe dementia patients attending outpatient clinics and inpatien ts in Ain Shams University Hospitals. Demographic data of the patients and their caregivers were collected. A questionnaire was applied on caregivers including types of burden they experienced, types of support they needed and their knowledge about dementi a & its effect on patients' life. Results: Most caregivers had different types of caregiving burdens. Ninety -eight percent (98%) of them had fear of future burden, 89% had physical& psychological burden and 69% had financial burden. Most caregivers needed support in caregiving. Eighty percent (80%) of them needed medical support, 59.4% needed physical support, 54.5% needed psychological support, 47.5% needed financial support, while only 8.9% needed social support. None of the caregivers had accurate previous knowledge about dementia. Ninety -three percent (93%) of caregivers predicted that dementia patients might need special care. Regarding dementia effect on patients, 88.1% of caregivers knew it had an effect on patients' behavior, 74.3 % knew it affects s leep, 54.5% knew it affects safety, 53.5% agreed with its effect on patients' activity and 48.5% knew it affects nutrition Conclusion: Caregiving of moderate to severe and severe dementia patients is associated with huge physical, psychological and financi al burdens. Most of the caregivers are in need of more support and knowledge to help them alleviate their burden and improve patients' care and q uality of life