Introduction: the act of caregiving for a relative, despite being a noble attitude, is related to a substantial risk of diseases, physical and mental, to the person who acts as an informal caregiver. Since it is a complex process, it may lead to the caregiver's burden and compromise his or her life quality. Objective: evaluate the burden of informal caregivers of patients who are assisted by a Healthcare Service. Method: cross research, descriptive, not experimental, of quantitative approach, with a group of 79 patients and their respective informal caregivers. Data was obtained by a profiling instrument of the participants, applying of Karnofsky Performance Score (KPS) and Zarit's Scale, Burden Interview, analyzed by descriptive statistics, correlation and comparing of the average results. Results: among the informal caregivers, it was verified that the average age is 55 years, are mostly women (93,70%), married (64,60%), has a high school degree (27,80%) and housewives (19,00%). Among the health diseases, prevail the circulatory system diseases (30,80%) and use of antihypertensive drugs (30,38%). It was identified the occurrence of pain (73,42%), rated as intense (43,10%), and use of public health services (93,70%), with two medical checks last year. It was possible to verify that 94,90% of the informal caregivers lived at the same home as the patient, with an average of 03 people per domicile; 67,10% did not receive the spouse's support for caregiving, but 63,30% of them reported someone else's cooperation. The observed average time of caregiving was of 24 hours per week; 13,90% gives care for other sick people and the prevailing degree of relatedness is son /daughter (38,00%). Absence from work was not identified. Among the reported tasks, helping the person to get dressed stood out (89,90%). 82,30% of the caregivers mentioned the occurrence of interruption of sleeping (82,30%)average of six hours per night. Among the patients, it was verified that the average age is 71 years, male (51,90%), married /in a stable union (43,00%), did not complete elementary school (39,20%), has an average of 03 sons, househusbands (17,70%), owner of its own domicile place, users of psychotropic substances and prevailing diagnosis of neurological system diseases (58,23%). Use of diapers is the predominant adopted measurement (72,20%). Identified performance status (KPS) between 50-60 (70,88%). About the informal caregiver's burden, it was rated as moderate level, being influenced by the age of the caregiver (p=0,016), age of the patient (p=0,047) and use of the gastrostomy device (p=0,011). Conclusion: collected data indicates that the homecare multiprofessional teams shall propose individual actions to the informal caregivers, as well as the public health services shall have proper places to teach them according to institutional protocols directed to them, aiming to reduce the burden levels and consequently offering a better quality of life.