Objectives To study the demography, clinical characteristics, service utilisation, mortality, and predictors of mortality in older residential care home residents with advanced cognitive impairment. Design Cohort longitudinal study. Setting Residential care homes for the elderly in Hong Kong West. Participants Residents of such homes aged 65 years or more with advanced cognitive impairment. Results In all, 312 such residential care home residents (71 men and 241 women) were studied. Their mean age was 88 (standard deviation, 8) years and their mean Barthel Index 20 score was 1.5 (standard deviation, 2.0). In all, 164 (53%) were receiving enteral feeding. Nearly all of them had urinary and bowel incontinence. Apart from Community Geriatric Assessment Team clinics, 119 (38%) of the residents attended other clinics outside their residential care homes. In all, 107 (34%) died within 1 year; those who died within 1 year used significantly more emergency and hospital services (P<0.001), and utilised more services from community care nurses for wound care (P=0.001), enteral feeding tube care (P=0.018), and urinary catheter care (P<0.001). Independent risk factors for 1-year mortality were active pressure sores (P=0.0037), enteral feeding (P=0.008), having a urinary catheter (P=0.0036), and suffering from chronic obstructive pulmonary disease (P=0.011). A history of pneumococcal vaccination was protective with respect to 1-year mortality (P=0.004). Conclusion Residents of residential care homes for the elderly with advanced cognitive impairment were frail, exhibited multiple comorbidities and high mortality. They were frequent users of outpatient, emergency, and in-patient services. The development of end-of-life care services in residential care homes for the elderly is an important need for this group of elderly.