Chronic diseases show a significant limitation on the quality of life and functional status, as patients as also their caregivers. The objective of this study is to analyse the quality of life of patients diagnosed with chronic obstructive pulmonary disease and stroke and their caregivers, and to find out if there is a relationship between the caregiver's overload and the quality of life of the patient, as well as to determine whether the functional status of the patients is related to the quality of life of the caregiver. Quantitative, observational, descriptive, cross-sectional and prospective study, performed at Primary Health Care Centres of the northwest Area of Murcia Region (Spain), between January and May 2018, with 131 patients, 79 with stroke, 48 with chronic obstructive pulmonary disease (4 of them with both diseases), and 110 caregivers. The EuroQol scale, Zarit's questionnaire and Barthel's index and an ad hoc questionnaire of sociodemographic variables developed for this study were used.We found a positive and significant correlation between the scores of the caregiver's overload scale and those of the caregiver's health status (r = −0.425; p = 0.001), and a negative and also significant correlation between the overload and quality of life of the patients (r = −0.297; p = 0.002) and their inability (r = 0.189; p = 0.048). The more the overload we find the worse quality of life of the caregiver, but better quality of life of the patient. The physical inability of the patients also influences on the caregiver's level of overload, but not in his health status. Intervention programmes are needed to improve the quality of life of family members as they are the best patient support and the best help for healthcare professionals.