Cancer impacts not only the patient but also the family members who share the distressing trajectory of the patient. The literature indicates that caregivers have many unmet information needs while providing care and support to the cancer patients, and caregivers have to resort to seeking information to supplement their information needs. This study aims to establish the prevalence of health-information-seeking behaviours among caregivers of cancer patients as a means of ascertaining if their information needs have been met and their information source and resource preference. Data were obtained via a self-reported questionnaire from caregivers of cancer patients at the National Cancer Centre Singapore between 10 September and 7 December 2018. A total of 986 caregivers responded of which 180 (18%) caregivers did not undertake information search and the common reasons were 'trust healthcare professionals' (HCPs) more than other sources (64%), and 'HCPs provide enough information' (59%). Among the 795 caregivers who have searched for cancer information, about half of these caregivers (54%) have searched information on the Internet and another 15% have obtained their information from HCPs in their most recent search. A total of 371 (47%) caregivers have used their preferred source of information to conduct their most recent information search. The top three most commonly sought information was treatment (35.6%), disease (35.6%) and side effects (26.5%). Almost half (46%) of these caregivers was concerned about the quality of information they have found on the Internet. Our study supports that information-seeking is prevalent amongst caregivers of cancer patients and reveals the prevalence of Internet use and the concerns associated with its use. Patterns of information-seeking revealed a discrepancy between preferred and actual source. The results also suggest that HCPs play a significant role in the information-seeking behaviours of caregivers of cancer patients.