This is a descriptive cross-sectional study that assessed the degree of burden on family caregivers of oncological patients, that are users of Clínica Cancerológica. Using a non probabilistic sampling and verifying the inclusion criteria, we studied 170 participants to whom we applied the Sociodemographic Characterization Survey and the Zarit Scale for assessing Caregiver Burden. In general, it is concluded that the degree of burden on caregivers is high in 79.4%. Also, in the physical (78.2%), psychological (43.5%), social (45.9%) and economical dimensions (88.8%) the same behavior was reported. Such situation highlights the heavy burden caused by the act of caring for a relative with oncological disease in the caregiver's life.