Background: This study assesses the use of formal and informal care resources among home-dwelling persons with dementia during the last month before nursing home admission. It also describes providers of informal care and assesses clinical and sociodemographic factors associated with the use of care stratified by living situation. Methods: In this cross-sectional study, data were collected from 47 nursing homes in four counties in Norway from January 2012 to August 2014. The subjects were persons with dementia who were newly admitted to a permanent nursing home. The main outcome measures were the use of formal care and informal care by the family caregiver and the extended social network. Results: A total of 395 persons were included. The amount of informal care provided by the family caregiver was 141.9 hours (SD=227.4). Co-resident patients received five times more informal care than non-co-residents. Informal care from the extended social network was provided to 212 patients (53.7%) with a mean of 5.6 (SD=11.2) hours per month. Formal care was provided to 52.7% of the patients with a mean of 18.0 (SD=50.1) hours per month. Co-residency was significantly associated with more informal care, and the associations varied with respect to age, relation to the caregiver, and the caregiver’s working situation. Good/excellent general health was associated with less formal care. Conclusion: Persons with dementia on the verge of admission to a nursing home are mostly supported by the family caregiver, and the use of informal care is particularly high among co-residents. Future research should explore the unrealized care potential in extended social networks, as well as the potential for increasing the number of recipients and utilization of formal care services directed at persons with dementia and their caregivers in order to delay nursing home admission.