COVID-19 pandemic in Argentina has affected the care of older adults with dementia deeply. Our objective was to study how the obligatory social isolation affected stress caregiver and burden of care of family members of subjects living with dementia in the community after the initial 4 weeks of quarantine in our setting. We did a questionnaire survey among 80 family caregivers of persons with Alzheimer’s disease (AD) or related dementia collected on April 2020. We designed a visual analog scale to test the level of the burden of care. Characteristics of people with dementia and their caregivers were analyzed with descriptive (mean, standard deviation, frequency and percent) and inferential statistics (chi-square test). The sample included older adults (mean age: 80.51 ± 7.65) with different stages of dementia. Family was the primary provider of care in 65%. Overall, COVID-19 confinement increased stress caregiver independently of the dementia stage, but those caring for severe cases had more stress compared to milder forms of the disease. Other findings were that half of the subjects with dementia experienced increased anxiety and that most family members discontinued all sort of cognitive and physical therapies. Family members’ main concerns were for severe dementia cases, fear of absence of the paid caregiver during the epidemic, and for mild cases fear of spreading the disease while assisting patients with instrumental activities. A partnership between departments of public health, care workers and families must be planned to guarantee continuity of care during these unique COVID-19 times.