Background: Cancer is a serious disease placing the family caregiver at a higher risk of burden which is a significant issue for caregivers who caring for elderly cancer patients. Aim of the study was to evaluate the effect of educational guidelines for family caregivers of elderly cancer patients regarding burden of care. Design: A quasiexperimental design was used. Setting: The study was conducted at Oncology Out-Patient Clinic in Benha teaching Hospital. Subjects: Simple random sample were used; it includes 200 patients, and their family caregivers were chosen randomly from the mentioned setting. Tools of data collection: Four tools were used. I- A structured interviewing questionnaire: Consisted of 2 parts to assess: 1) Demographic characteristics of elderly cancer patients and their caregivers: 2) Medical history of the elderly cancer patients. Tool II: The family caregiver's knowledge about cancer disease. Tool III: Family caregivers' reported practices. Tool IV: Zarit Burden Interview to assess family caregivers' burden of care. Results: There were general improvements regarding family caregivers' knowledge and practice regarding cancer with highly significant difference (P≤0.001), and family caregivers' burden of care decreased to 40.5% post educational guideline. There was highly statistically significant correlation between total knowledge, total practices, and total burden scores of the studied family caregivers. Conclusion: The educational guidelines had a significant effect there was a significant decrease in family caregivers' burden of care. There was highly statistically significant correlation between total knowledge, total practices, and total burden scores of the studied family caregivers for elderly patients with cancer. Recommendations: Advocate family caregivers about supportive services help in caring elderly people with cancer.