This research investigated two groups of patients diagnosed with dementia before the age of sixty-five. The patients were diagnosed with Alzheimer’s Disease (AD, n = 25) and Frontotemporal Dementia (FTD, n = 37). Patients were assessed for approximately 3 years. The study found that FTD is a valid and useful diagnostic category, and can be reliably differentiated from AD. A combination of behavioural, neurological, and neuropsychological assessments were found to be complementary in the early and accurate diagnosis of early-onset dementia, and the differential diagnosis of FTD from AD. FTD patients were found to have relatively preserved visuo-spatial abilities compared to the AD patients. Problems associated with administering neuropsychological tests to early-onset dementia patients were highlighted. FTD patients were found to deteriorate more rapidly than AD patients, and to have significantly increased behavioural disturbances throughout the course of the illness in comparison with the AD patients. Practical guidelines to assist with care and management of early-onset dementia patients were presented. A strengths-based model of care was outlined. Individualised assessments and care plans were recommended for the development and provision of humane services to early-onset dementia patients. Issues surrounding providing palliative care were discussed.