Aim This study identified the moderating role of the amount of caregiving tasks on relationships between dementia family caregivers’ characteristics (age, education, etc.) and outcomes (burden, etc.). Design A cross‐sectional analysis of surveyed data. Method A convenience sample of 369 family caregivers (151 males, 218 females) aged 20 years or older was recruited from 10 cities in the southern area of South Korea. Data were collected from November–December 2011. Measures of caregiver burden, perceived health status and emotional distress of caregivers related to the memory‐behaviour problems of the care recipient were used to assess the outcomes of family caregivers of older adults with dementia. Results The amount of caregiving tasks has a moderating effect on the relationships between caregivers’ characteristics (such as living with the recipient and duration of caregiving) and the caregiver burden. The interaction between the amount of caregiving tasks and status of living with recipient was significant in relation to the emotional distress of caregivers related to the memory‐behaviour problems of the care recipient with dementia; however, there was no effect of the amount of caregiving tasks on the relationships between caregivers’ characteristics and perceived health status. Conclusion The amount of caregiving tasks can have a moderating role in the caregiving stress model. Intervention programs need to be developed and implemented to reduce negative outcomes of family caregivers, particularly those living with older adults with dementia.