Objective: To evaluate the effect of an educational intervention on family caregivers of adults with cancer who are in the postoperative period of oncological surgery, to strengthen the competence of home care and reduce overload. Method: This was a quasi-experimental quantitative approach with intervention group and control group; 290 family caregivers of patients undergoing surgery were included, educational intervention was applied from admission to six weeks after discharge, measurement was made before and after competence for home care and care overload. Results: In the group intervened, a positive and statistically significant impact was obtained in the competence for home care and decreased overload. Conclusions: The educational intervention is a strategy that increases skills for care at home, and reduces the burden on caregivers of people with cancer undergoing surgery.