Introduction: Singapore is facing a rapidly ageing population with its antecedent care needs. A greater understanding of informal caregiver burden and how primary care physicians can support them is therefore needed. This study investigated the contributing factors to caregiver burden in Singapore. Methods: Eighty caregivers of elderly receiving eldercare services were randomly selected to take part in a modified Singapore Survey on Informal Caregiving. The Zarit Burden Interview was used to measure caregiver burden. Logistic regression and chi-square tests were performed to analyse the difference in factors between high and low burden caregivers. Results: Five variables were significantly associated with level of burden. High burden caregivers were found to have a lower mean age, less positive feelings towards caregiving, more disrupted schedules, more health problems, and less self-esteem derived from caregiving. Conclusion: The factors affecting caregiver burden are multifaceted, with caregiving having an impact on various domains of a caregiver’s life. Understanding these factors will help primary care physicians provide more holistic care for the elderly in the context of their family.