BackgroundThe use of online and mobile internet and social media has been increasing in healthcare service delivery. However, there is limited literature on the acceptance and use of online health services for older adults with multimorbidity who require more medical care and assistance. This study aims to explore the use of social media in older adults with multimorbidity in Hong Kong primary care and to assess the feasibility and usage of online health services in this population, including satisfaction, preference, and problems encountered.MethodsThis is a cross-sectional study among older adults with multimorbidity conducted between November 2020 and March 2021 in a Hong Kong primary care programme. Online and face-to-face services were offered based on the needs of the participants. Demographic characteristics and health conditions were assessed at baseline. Participants using online services were invited to complete a feedback questionnaire.ResultsThe study included 752 participants, of which 66.1% use social media every day. Participants who declined to use online services were found to be significantly older, live alone, have lower income, have social security assistance, have greater cognitive decline, and be less depressed (p < 0.05). Non-responders to the online questionnaire had fewer years of education and greater cognitive decline (p < 0.05). The median satisfaction with the online services was 8 (interquartile range: 7, 9), and 14.6% of the participants preferred online more than face-to-face services. Lower education levels, fewer internet connection issues, and more self-efficacy on mobile apps were associated with a higher level of online satisfaction after adjustment (p < 0.05). Fewer internet connection issues and more self-efficacy on mobile apps were associated with participants’ preference for online services (p < 0.05).ConclusionsMore than half of Hong Kong older adults with multimorbidity in primary care use social media daily. Internet connection issues can be a significant barrier to the usage of online services in this population. Prior use and training can be beneficial to enhance use and satisfaction in older adults.