PURPOSE: Although home care improves patients' quality of life (QOL), several studies have suggested that home care lowers the QOL of family caregivers and decreases their mortality. To alleviate the deleterious impact of home care on caregivers, the major burdens on caregivers and the clinical characteristics of the caregivers vulnerable to the major burden needs to be clarified. METHOD: A survey questionnaire was distributed to 710 family caregivers of patients with cancer in Japan, and 342 valid responses were obtained (valid response rate: 48.2%). The Burden Index of Caregivers was used to identify the major burden on caregivers. To assess the associations of the patients' care needs level and other clinically relevant factors with the major burden, a multivariable-adjusted logistic regression model was used. RESULTS: The time-dependent burden was identified as a major burden. An adjusted model showed a nonlinear association between the care needs level and the time-dependent burden, in which the caregivers of the patients who required moderate care needs level had the highest time-dependent burden [adjusted odds ratio of none, mild, moderate, and severe care needs levels: 0.50 (95% confidence interval 0.07-2.12), 1.08 (0.43-2.57), 1.87 (1.01-3.52), and 1.00 (reference), respectively]. Additionally, older patients and younger caregivers were significantly associated with a time-dependent burden. CONCLUSION: The time-dependent burden was highest in caregivers at the moderate care needs level and younger caregivers. An imbalance between the demand and supply of care services may be improved by considering the clinical characteristics of both patients and caregivers.