Background: There is insufficient research into informal caregivers' quality of life (QoL) in Poland. The purpose of this work is to study predictors that considerably affect QoL of informal caregivers (IC) providing home care for seniors with chronic diseases and a functional performance deficit. Materials and methods: In the cross-sectional research design, ICs were randomly chosen among the geriatric population receiving care in 5 primary health care settings. The WHOQoL-AGE questionnaire was used to assess QoL of ICs (n=138). The Barthel scale and Polish version of the Abbreviated Mental Test Score (AMTS) were applied to assess individuals with chronic diseases and functional and mental performance deficits (n=138). The Geriatric Depression Scale Short Form (GDS-SF) was used to measure the extent of risk of depressive symptoms in care-receivers. A hierarchical regression analysis was carried out to determine predictors of caregivers' QoL. Results: Mean values in the group of seniors provided with home care were as follows: the Barthel scale M=43.20, SD=27.06, the AMTS M=7.78 (SD=1.65), and the GDS-SF M=7.34 (SD=3.10). QoL of ICs (the WHOQoL-AGE) was M=70.14 (SD=15.31). Significant predictors of caregivers' QoL turned out to be support in care given by others β =0.605, p<0.001, experience in care β =-0.220; p<0.001, caregivers' health self-assessment β =0.174, p<0.001, and depressive disorders in care-receivers GDS β = −0.178, p<0.001. Conclusions: The QoL of ICs who provide care for individuals with chronic diseases and a functional performance deficit improves with an increase in the support they receive from others, their higher health self-assessment, and greater experience in care. An increase in depressive symptoms in care-receivers determines a lower level of caregivers' QoL.